1. Brainstem gliomas are tumors that arise within the brainstem and can be diffuse or focal. Diffuse infiltrating pontine gliomas (DIPGs) represent 60-75% of pediatric brainstem gliomas and typically present with cranial nerve palsies, ataxia, and long tract signs.
2. Magnetic resonance imaging is the preferred method for diagnosis and shows characteristic features for DIPGs including diffuse enlargement and T2 hyperintensity of the pons.
Surgical approach to thalamus explained in details their surgical anatomy and lesion, Preop post op results with different surgical approach for thalamic lesions
The fifth edition of the WHO Classification of Tumors of the Central Nervous System (WHO CNS5) incorporates numerous molecular changes with clinicopathologic utility that are important for the most accurate classification of CNS neoplasms.
WHO CNS5 does not recommend specific methods for molecular assessment.
WHO CNS5 has grouped tumors according to the genetic changes that enable a complete diagnosis.
IDH (Astrocytoma, Oligodendroglioma and Glioblastoma) and H3 (Diffuse midline glioma, Diffuse hemispheric glioma).
Some by looser oncogenic associations. Like MAPK pathway alteration (Multinodular and Vacuolating Neuronal Tumor).
Some are classified by histological similarities even though molecular signatures vary.
Atypical teratoid/rhabdoid tumor, Ganglioglioma, Papillary glioneuronal tumor.
Many by using molecular features to define new types and subtypes.
Medulloblastoma.
The term “type" is used instead of “entity” and “subtype” is used instead of “variant".
The fifth edition of the WHO Classification of Tumors of the Central Nervous System follows the recommendations of the 2019 cIMPACT-NOW Utrecht meeting.
Names have been simplified, and only location, age, or genetic modifiers with clinical utility have been used.
Extra-ventricular neurocytoma vs Central neurocytoma.
The characteristics of tumors that are highly characteristic are included in tumor definitions and descriptions, even if they do not appear in the tumor name itself.
chordoid gliomas occurring in the third ventricle
Sometimes tumor names reflect morphologic features that are not present in every example, and they may also reflect historical associations.
Some myxopapillary ependymomas are minimally myxoid, and some may not be overtly papillary.
Xanthomatous change may be limited to a small fraction of cells in pleomorphic xanthoastrocytomas.
Medulloblast has not been identified in developmental studies, in cases of Medulloblastoma.
As they would be disruptive to clinicians and may lead to confusion, they were not changed.
Tumors are now graded within types, modifier terms like "anaplastic" are not routinely used.
Surgical approach to thalamus explained in details their surgical anatomy and lesion, Preop post op results with different surgical approach for thalamic lesions
The fifth edition of the WHO Classification of Tumors of the Central Nervous System (WHO CNS5) incorporates numerous molecular changes with clinicopathologic utility that are important for the most accurate classification of CNS neoplasms.
WHO CNS5 does not recommend specific methods for molecular assessment.
WHO CNS5 has grouped tumors according to the genetic changes that enable a complete diagnosis.
IDH (Astrocytoma, Oligodendroglioma and Glioblastoma) and H3 (Diffuse midline glioma, Diffuse hemispheric glioma).
Some by looser oncogenic associations. Like MAPK pathway alteration (Multinodular and Vacuolating Neuronal Tumor).
Some are classified by histological similarities even though molecular signatures vary.
Atypical teratoid/rhabdoid tumor, Ganglioglioma, Papillary glioneuronal tumor.
Many by using molecular features to define new types and subtypes.
Medulloblastoma.
The term “type" is used instead of “entity” and “subtype” is used instead of “variant".
The fifth edition of the WHO Classification of Tumors of the Central Nervous System follows the recommendations of the 2019 cIMPACT-NOW Utrecht meeting.
Names have been simplified, and only location, age, or genetic modifiers with clinical utility have been used.
Extra-ventricular neurocytoma vs Central neurocytoma.
The characteristics of tumors that are highly characteristic are included in tumor definitions and descriptions, even if they do not appear in the tumor name itself.
chordoid gliomas occurring in the third ventricle
Sometimes tumor names reflect morphologic features that are not present in every example, and they may also reflect historical associations.
Some myxopapillary ependymomas are minimally myxoid, and some may not be overtly papillary.
Xanthomatous change may be limited to a small fraction of cells in pleomorphic xanthoastrocytomas.
Medulloblast has not been identified in developmental studies, in cases of Medulloblastoma.
As they would be disruptive to clinicians and may lead to confusion, they were not changed.
Tumors are now graded within types, modifier terms like "anaplastic" are not routinely used.
Pituitary tumor accounts for ~10% ICT. They are common in 3-4 decade and shows association with MEN I.
About 5% of PT are invasive usually with giant tumor (>4cm). Tumor can be classified as functional (hormone secreting) or non functional. This slides details the algorithmic approach in management of pituitary tumors.
Neuroimaging of Alzheimer’s disease and Healthy Aging
BY DR WASIM
UNDER THE GUIDANCE OF
DR R.K.SOLANKI
ANATOMICAL BRAIN IMAGING
CT – cerebral tomography
MRI – magnetic resonance imaging
FUNCTIONAL BRAIN IMAGING
SPECT – single photon emission computed tomography
PET – FDG – Positron emission tomography
BRAIN CHEMISTRY MEASUREMENT
MRS (spectroscopy – NAA/Cr: estimate neuronal volume)
BRAIN PATHOLOGY IMAGING
FDDNP – neurofibrillary pathology
Evolution of Neuroimaging in AD
Computed Tomography
MRI
Volumetric MRI
Functional MRI
FDG Glucose PET
Amyloid Imaging
FDG-PET in AD and MCI
Anatomy of Brain by MRI
In this presentation we will discuss the cross sectional anatomy of brain. Then we will discuss the Most common diseases to be evaluated by brain imaging.
In my opinion this presentation is a road map for beginars.
Foramen magnum meningiomas are challenging tumors, requiring special considerations because of the vicinity of the medulla oblongata, the lower cranial nerves, and the vertebral artery. It accounts for 1-3% of all intracranial Meningioma.
I am a Neurosurgeon with advanced training in Interventional vascular Neurosurgery(FINR) from Zurich, Switzerland, and FMINS-Fellowship in minimally invasive and Endoscopic Neurosurgery from Germany.
I am presently working in Columbia asia hospitals, Bangalore.
My areas of interest are Vascular Neurosurgery, Stroke specialist, interventional neuroradiology.
In this presentation we will dscuss the imp imaging features of Posterior fossa tumors in pediatric age group.
Medulloblastoma
Pilocytic Astrocytoma
Ependymoma
Brainstem Glioma
Schwanoma
Meningioma
Epidermoid Cyst
Arachnoid Cyst
Pituitary tumor accounts for ~10% ICT. They are common in 3-4 decade and shows association with MEN I.
About 5% of PT are invasive usually with giant tumor (>4cm). Tumor can be classified as functional (hormone secreting) or non functional. This slides details the algorithmic approach in management of pituitary tumors.
Neuroimaging of Alzheimer’s disease and Healthy Aging
BY DR WASIM
UNDER THE GUIDANCE OF
DR R.K.SOLANKI
ANATOMICAL BRAIN IMAGING
CT – cerebral tomography
MRI – magnetic resonance imaging
FUNCTIONAL BRAIN IMAGING
SPECT – single photon emission computed tomography
PET – FDG – Positron emission tomography
BRAIN CHEMISTRY MEASUREMENT
MRS (spectroscopy – NAA/Cr: estimate neuronal volume)
BRAIN PATHOLOGY IMAGING
FDDNP – neurofibrillary pathology
Evolution of Neuroimaging in AD
Computed Tomography
MRI
Volumetric MRI
Functional MRI
FDG Glucose PET
Amyloid Imaging
FDG-PET in AD and MCI
Anatomy of Brain by MRI
In this presentation we will discuss the cross sectional anatomy of brain. Then we will discuss the Most common diseases to be evaluated by brain imaging.
In my opinion this presentation is a road map for beginars.
Foramen magnum meningiomas are challenging tumors, requiring special considerations because of the vicinity of the medulla oblongata, the lower cranial nerves, and the vertebral artery. It accounts for 1-3% of all intracranial Meningioma.
I am a Neurosurgeon with advanced training in Interventional vascular Neurosurgery(FINR) from Zurich, Switzerland, and FMINS-Fellowship in minimally invasive and Endoscopic Neurosurgery from Germany.
I am presently working in Columbia asia hospitals, Bangalore.
My areas of interest are Vascular Neurosurgery, Stroke specialist, interventional neuroradiology.
In this presentation we will dscuss the imp imaging features of Posterior fossa tumors in pediatric age group.
Medulloblastoma
Pilocytic Astrocytoma
Ependymoma
Brainstem Glioma
Schwanoma
Meningioma
Epidermoid Cyst
Arachnoid Cyst
Detailed Description about soft tissue sarcoma.
Deals with topics including etiology, histopathology,clinical presentation ,staging and prognostic factors and management methods including surgery and adjuvent therapy .
Soft tissue sarcomas are a heterogeneous group of malignant tumours derived from primitive mesenchymal cells.
They are aggressive tumours which are locally invasive and recurrent.
They are named based on the cell of origin .
They require multimodal treatment including surgery and certain adjuvent therapies
Title: Sense of Smell
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the primary categories of smells and the concept of odor blindness.
Explain the structure and location of the olfactory membrane and mucosa, including the types and roles of cells involved in olfaction.
Describe the pathway and mechanisms of olfactory signal transmission from the olfactory receptors to the brain.
Illustrate the biochemical cascade triggered by odorant binding to olfactory receptors, including the role of G-proteins and second messengers in generating an action potential.
Identify different types of olfactory disorders such as anosmia, hyposmia, hyperosmia, and dysosmia, including their potential causes.
Key Topics:
Olfactory Genes:
3% of the human genome accounts for olfactory genes.
400 genes for odorant receptors.
Olfactory Membrane:
Located in the superior part of the nasal cavity.
Medially: Folds downward along the superior septum.
Laterally: Folds over the superior turbinate and upper surface of the middle turbinate.
Total surface area: 5-10 square centimeters.
Olfactory Mucosa:
Olfactory Cells: Bipolar nerve cells derived from the CNS (100 million), with 4-25 olfactory cilia per cell.
Sustentacular Cells: Produce mucus and maintain ionic and molecular environment.
Basal Cells: Replace worn-out olfactory cells with an average lifespan of 1-2 months.
Bowman’s Gland: Secretes mucus.
Stimulation of Olfactory Cells:
Odorant dissolves in mucus and attaches to receptors on olfactory cilia.
Involves a cascade effect through G-proteins and second messengers, leading to depolarization and action potential generation in the olfactory nerve.
Quality of a Good Odorant:
Small (3-20 Carbon atoms), volatile, water-soluble, and lipid-soluble.
Facilitated by odorant-binding proteins in mucus.
Membrane Potential and Action Potential:
Resting membrane potential: -55mV.
Action potential frequency in the olfactory nerve increases with odorant strength.
Adaptation Towards the Sense of Smell:
Rapid adaptation within the first second, with further slow adaptation.
Psychological adaptation greater than receptor adaptation, involving feedback inhibition from the central nervous system.
Primary Sensations of Smell:
Camphoraceous, Musky, Floral, Pepperminty, Ethereal, Pungent, Putrid.
Odor Detection Threshold:
Examples: Hydrogen sulfide (0.0005 ppm), Methyl-mercaptan (0.002 ppm).
Some toxic substances are odorless at lethal concentrations.
Characteristics of Smell:
Odor blindness for single substances due to lack of appropriate receptor protein.
Behavioral and emotional influences of smell.
Transmission of Olfactory Signals:
From olfactory cells to glomeruli in the olfactory bulb, involving lateral inhibition.
Primitive, less old, and new olfactory systems with different path
Report Back from SGO 2024: What’s the Latest in Cervical Cancer?bkling
Are you curious about what’s new in cervical cancer research or unsure what the findings mean? Join Dr. Emily Ko, a gynecologic oncologist at Penn Medicine, to learn about the latest updates from the Society of Gynecologic Oncology (SGO) 2024 Annual Meeting on Women’s Cancer. Dr. Ko will discuss what the research presented at the conference means for you and answer your questions about the new developments.
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Ve...kevinkariuki227
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
Title: Sense of Taste
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the structure and function of taste buds.
Describe the relationship between the taste threshold and taste index of common substances.
Explain the chemical basis and signal transduction of taste perception for each type of primary taste sensation.
Recognize different abnormalities of taste perception and their causes.
Key Topics:
Significance of Taste Sensation:
Differentiation between pleasant and harmful food
Influence on behavior
Selection of food based on metabolic needs
Receptors of Taste:
Taste buds on the tongue
Influence of sense of smell, texture of food, and pain stimulation (e.g., by pepper)
Primary and Secondary Taste Sensations:
Primary taste sensations: Sweet, Sour, Salty, Bitter, Umami
Chemical basis and signal transduction mechanisms for each taste
Taste Threshold and Index:
Taste threshold values for Sweet (sucrose), Salty (NaCl), Sour (HCl), and Bitter (Quinine)
Taste index relationship: Inversely proportional to taste threshold
Taste Blindness:
Inability to taste certain substances, particularly thiourea compounds
Example: Phenylthiocarbamide
Structure and Function of Taste Buds:
Composition: Epithelial cells, Sustentacular/Supporting cells, Taste cells, Basal cells
Features: Taste pores, Taste hairs/microvilli, and Taste nerve fibers
Location of Taste Buds:
Found in papillae of the tongue (Fungiform, Circumvallate, Foliate)
Also present on the palate, tonsillar pillars, epiglottis, and proximal esophagus
Mechanism of Taste Stimulation:
Interaction of taste substances with receptors on microvilli
Signal transduction pathways for Umami, Sweet, Bitter, Sour, and Salty tastes
Taste Sensitivity and Adaptation:
Decrease in sensitivity with age
Rapid adaptation of taste sensation
Role of Saliva in Taste:
Dissolution of tastants to reach receptors
Washing away the stimulus
Taste Preferences and Aversions:
Mechanisms behind taste preference and aversion
Influence of receptors and neural pathways
Impact of Sensory Nerve Damage:
Degeneration of taste buds if the sensory nerve fiber is cut
Abnormalities of Taste Detection:
Conditions: Ageusia, Hypogeusia, Dysgeusia (parageusia)
Causes: Nerve damage, neurological disorders, infections, poor oral hygiene, adverse drug effects, deficiencies, aging, tobacco use, altered neurotransmitter levels
Neurotransmitters and Taste Threshold:
Effects of serotonin (5-HT) and norepinephrine (NE) on taste sensitivity
Supertasters:
25% of the population with heightened sensitivity to taste, especially bitterness
Increased number of fungiform papillae
- Video recording of this lecture in English language: https://youtu.be/lK81BzxMqdo
- Video recording of this lecture in Arabic language: https://youtu.be/Ve4P0COk9OI
- Link to download the book free: https://nephrotube.blogspot.com/p/nephrotube-nephrology-books.html
- Link to NephroTube website: www.NephroTube.com
- Link to NephroTube social media accounts: https://nephrotube.blogspot.com/p/join-nephrotube-on-social-media.html
NVBDCP.pptx Nation vector borne disease control programSapna Thakur
NVBDCP was launched in 2003-2004 . Vector-Borne Disease: Disease that results from an infection transmitted to humans and other animals by blood-feeding arthropods, such as mosquitoes, ticks, and fleas. Examples of vector-borne diseases include Dengue fever, West Nile Virus, Lyme disease, and malaria.
Lung Cancer: Artificial Intelligence, Synergetics, Complex System Analysis, S...Oleg Kshivets
RESULTS: Overall life span (LS) was 2252.1±1742.5 days and cumulative 5-year survival (5YS) reached 73.2%, 10 years – 64.8%, 20 years – 42.5%. 513 LCP lived more than 5 years (LS=3124.6±1525.6 days), 148 LCP – more than 10 years (LS=5054.4±1504.1 days).199 LCP died because of LC (LS=562.7±374.5 days). 5YS of LCP after bi/lobectomies was significantly superior in comparison with LCP after pneumonectomies (78.1% vs.63.7%, P=0.00001 by log-rank test). AT significantly improved 5YS (66.3% vs. 34.8%) (P=0.00000 by log-rank test) only for LCP with N1-2. Cox modeling displayed that 5YS of LCP significantly depended on: phase transition (PT) early-invasive LC in terms of synergetics, PT N0—N12, cell ratio factors (ratio between cancer cells- CC and blood cells subpopulations), G1-3, histology, glucose, AT, blood cell circuit, prothrombin index, heparin tolerance, recalcification time (P=0.000-0.038). Neural networks, genetic algorithm selection and bootstrap simulation revealed relationships between 5YS and PT early-invasive LC (rank=1), PT N0—N12 (rank=2), thrombocytes/CC (3), erythrocytes/CC (4), eosinophils/CC (5), healthy cells/CC (6), lymphocytes/CC (7), segmented neutrophils/CC (8), stick neutrophils/CC (9), monocytes/CC (10); leucocytes/CC (11). Correct prediction of 5YS was 100% by neural networks computing (area under ROC curve=1.0; error=0.0).
CONCLUSIONS: 5YS of LCP after radical procedures significantly depended on: 1) PT early-invasive cancer; 2) PT N0--N12; 3) cell ratio factors; 4) blood cell circuit; 5) biochemical factors; 6) hemostasis system; 7) AT; 8) LC characteristics; 9) LC cell dynamics; 10) surgery type: lobectomy/pneumonectomy; 11) anthropometric data. Optimal diagnosis and treatment strategies for LC are: 1) screening and early detection of LC; 2) availability of experienced thoracic surgeons because of complexity of radical procedures; 3) aggressive en block surgery and adequate lymph node dissection for completeness; 4) precise prediction; 5) adjuvant chemoimmunoradiotherapy for LCP with unfavorable prognosis.
ARTIFICIAL INTELLIGENCE IN HEALTHCARE.pdfAnujkumaranit
Artificial intelligence (AI) refers to the simulation of human intelligence processes by machines, especially computer systems. It encompasses tasks such as learning, reasoning, problem-solving, perception, and language understanding. AI technologies are revolutionizing various fields, from healthcare to finance, by enabling machines to perform tasks that typically require human intelligence.
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Ozempic: Preoperative Management of Patients on GLP-1 Receptor Agonists Saeid Safari
Preoperative Management of Patients on GLP-1 Receptor Agonists like Ozempic and Semiglutide
ASA GUIDELINE
NYSORA Guideline
2 Case Reports of Gastric Ultrasound
Flu Vaccine Alert in Bangalore Karnatakaaddon Scans
As flu season approaches, health officials in Bangalore, Karnataka, are urging residents to get their flu vaccinations. The seasonal flu, while common, can lead to severe health complications, particularly for vulnerable populations such as young children, the elderly, and those with underlying health conditions.
Dr. Vidisha Kumari, a leading epidemiologist in Bangalore, emphasizes the importance of getting vaccinated. "The flu vaccine is our best defense against the influenza virus. It not only protects individuals but also helps prevent the spread of the virus in our communities," he says.
This year, the flu season is expected to coincide with a potential increase in other respiratory illnesses. The Karnataka Health Department has launched an awareness campaign highlighting the significance of flu vaccinations. They have set up multiple vaccination centers across Bangalore, making it convenient for residents to receive their shots.
To encourage widespread vaccination, the government is also collaborating with local schools, workplaces, and community centers to facilitate vaccination drives. Special attention is being given to ensuring that the vaccine is accessible to all, including marginalized communities who may have limited access to healthcare.
Residents are reminded that the flu vaccine is safe and effective. Common side effects are mild and may include soreness at the injection site, mild fever, or muscle aches. These side effects are generally short-lived and far less severe than the flu itself.
Healthcare providers are also stressing the importance of continuing COVID-19 precautions. Wearing masks, practicing good hand hygiene, and maintaining social distancing are still crucial, especially in crowded places.
Protect yourself and your loved ones by getting vaccinated. Together, we can help keep Bangalore healthy and safe this flu season. For more information on vaccination centers and schedules, residents can visit the Karnataka Health Department’s official website or follow their social media pages.
Stay informed, stay safe, and get your flu shot today!
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New Directions in Targeted Therapeutic Approaches for Older Adults With Mantl...i3 Health
i3 Health is pleased to make the speaker slides from this activity available for use as a non-accredited self-study or teaching resource.
This slide deck presented by Dr. Kami Maddocks, Professor-Clinical in the Division of Hematology and
Associate Division Director for Ambulatory Operations
The Ohio State University Comprehensive Cancer Center, will provide insight into new directions in targeted therapeutic approaches for older adults with mantle cell lymphoma.
STATEMENT OF NEED
Mantle cell lymphoma (MCL) is a rare, aggressive B-cell non-Hodgkin lymphoma (NHL) accounting for 5% to 7% of all lymphomas. Its prognosis ranges from indolent disease that does not require treatment for years to very aggressive disease, which is associated with poor survival (Silkenstedt et al, 2021). Typically, MCL is diagnosed at advanced stage and in older patients who cannot tolerate intensive therapy (NCCN, 2022). Although recent advances have slightly increased remission rates, recurrence and relapse remain very common, leading to a median overall survival between 3 and 6 years (LLS, 2021). Though there are several effective options, progress is still needed towards establishing an accepted frontline approach for MCL (Castellino et al, 2022). Treatment selection and management of MCL are complicated by the heterogeneity of prognosis, advanced age and comorbidities of patients, and lack of an established standard approach for treatment, making it vital that clinicians be familiar with the latest research and advances in this area. In this activity chaired by Michael Wang, MD, Professor in the Department of Lymphoma & Myeloma at MD Anderson Cancer Center, expert faculty will discuss prognostic factors informing treatment, the promising results of recent trials in new therapeutic approaches, and the implications of treatment resistance in therapeutic selection for MCL.
Target Audience
Hematology/oncology fellows, attending faculty, and other health care professionals involved in the treatment of patients with mantle cell lymphoma (MCL).
Learning Objectives
1.) Identify clinical and biological prognostic factors that can guide treatment decision making for older adults with MCL
2.) Evaluate emerging data on targeted therapeutic approaches for treatment-naive and relapsed/refractory MCL and their applicability to older adults
3.) Assess mechanisms of resistance to targeted therapies for MCL and their implications for treatment selection
These simplified slides by Dr. Sidra Arshad present an overview of the non-respiratory functions of the respiratory tract.
Learning objectives:
1. Enlist the non-respiratory functions of the respiratory tract
2. Briefly explain how these functions are carried out
3. Discuss the significance of dead space
4. Differentiate between minute ventilation and alveolar ventilation
5. Describe the cough and sneeze reflexes
Study Resources:
1. Chapter 39, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 34, Ganong’s Review of Medical Physiology, 26th edition
3. Chapter 17, Human Physiology by Lauralee Sherwood, 9th edition
4. Non-respiratory functions of the lungs https://academic.oup.com/bjaed/article/13/3/98/278874
MANAGEMENT OF ATRIOVENTRICULAR CONDUCTION BLOCK.pdfJim Jacob Roy
Cardiac conduction defects can occur due to various causes.
Atrioventricular conduction blocks ( AV blocks ) are classified into 3 types.
This document describes the acute management of AV block.
3. • By definition, BSGs are tumors that arise
within the anatomic structures that make
up the brainstem (m i d b r a i n , t h e p o n s ,
o r t h e m e d u l l a o b l o n g a t a )
• This definition excludes patients with
tumors originating in the t h a l a m u s and
h y p o t h a l a m u s or lesions originating
in the c e r e b e l l u m , c e r e b e l l a r
p e d u n c l e s , or u p p e r c e r v i c a l
s p i n a l c o r d
4. <1980
• Because of its difficult
accessand
functional
importance, in the
past, the brainstem was
seldom
exploredby
neurosurgeons, with its injury
often conducive to deep coma
• For many years, a tumor
growing inside the brainstem
was considered
malignantin itself and
managed empirically as a
homogeneous
• B a i l e y et al (1939) - ‘BSG are a
hopeless problem for treatment’
• D a n d y (1962) - ‘ There is little
indication for attempting any
enucleation of the tumor in this
region
• M a t s o n (1969) - Regardless of
specific histology, brainstem
gliomas must be classified as
malignant tumors since their
location in itself renders them
inoperable
• B a k e r (1964) - published a
series of pts with ‘subependymal
gliomas’
• Pool (1968) - First
reported case of
surgical resection of
BST located in the area
5. >1980
• Gradual advancement in
mi cr osur gi cal
techni ques , sophisticated
imaging technology, most importantly
availability of MRI
• Identification of subcategor ies
of tumors which appear to have low -
gr ade pathologies and offer a better
prognosis
• D i f f e r e n t s e r i e s o n B S G s i n c e
7. • Location
• Focality
• Growth
• Imaging
• DIBG & Non
diffuse (Focal) BG
• F o c a l
- <50% of the axial
brainstem
diameter
• D i f f u s e
- Poorly
demarcated
8. • MIDBRAIN (7 - 8%)
- Almost always low-grade
pilocytic astrocytomas
(WHO I & II)
- Good prognosis
• PONS (80 %)
- Usually High grade
astrocytomas (WHO III &
IV)
- Dismal prognosis
• MEDULLA (10 - 15%)
- Usually low grade pilocytic
astrocytomas (WHO I & II)
- Good to fair prognosis
Brainstem gliomas – A clinicopathological study of 45 cases with p53
immunohistochemistry
Badhe Prerna B, Chauhan Pritika P, Mehta Nishaki K
Departments of Pathology, Seth G. S. Medical College and KEM Hospital,
9. Classification Schemes for Brain
Stem Tumors
Author Method Used to
Create System
Classification System
Epstein CT Intrinsic
Diffuse
Focal
Cervicomedullary
Exophytic
Anterolateral into CP angle
Posterolateral and into brachium pontis
Disseminated
Positive cytology
Positive myelography
Epstein
and
McCleary
CT, MRI, and
surgical
observation
Diffuse
Focal
Cervicomedullary
10. Classification Schemes for Brain
Stem Tumors
Author Method Used
to
Create System
Classification System
Stroink
etal
CT Group I
dorsal exophytic glioma
Group IIa
intrinsic brainstem tumors - Hypodense, no
enhancement
Group IIb
intrinsic brainstem tumors - Hyperdense,
contrast enhancing exophytic
Group III
focal cystic tumor with contrast
enhancement
11. Classification Schemes for Brain
Stem TumorsAuthor Method Used
to
Create System
Classification System
Barkovi
ch
MRI 1. Location (midbrain, pons,
medulla)
2. Focality (diffuse or focal)
3. Direction and extent of
tumor growth
4. Degree of brainstem
enlargement
5. Exophytic growth
6. Hemorrhage or necrosis
7. Evidence of hydrocephalus
Albrigh MRI 1. Focal (midbrain, pons,
12. Classification Schemes for Brain
Stem Tumors
Author Method Used to
Create System
Classification System
Fischbein
et al
MRI 1. Midbrain
Diffuse
Focal
Tectal
2. Pons
Diffuse
Focal
3. Medulla
Diffuse
Focal
4. Dorsal exophytic
Choux et al CT and MRI Type I—diffuse
Type II—intrinsic, focal
Type III—exophytic, focal
Type IV—cervicomedullary
13. Epstein & Farmer Classification
1. DIPG (80%)
2. Focal Tumors (5%)
a) Tectal tumors
b) Pontine tumors
c) Midbrain tumors
3. Dorsal exophytic tumors(10 -15%)
4. Tumors of the cervicomedullary junction
(CMJ) 5 -10%
• Thalamic tumors - considered some authors
• CMJ tumors - considered by most to be a subgroup of BSGs, although some
clinicians believe that they are the most cephalic extension of cervical
intramedullary spinal cord tumors
15. Ref : Brainstem gliomas – A clinicopathological study of
45 cases with p53 Immunohistochemistry
Badhe Prerna B, Chauhan Pritika P, Mehta Nishaki ;
Departments of Pathology, Seth G. S. Medical College
and KEM Hospital, Parel, Mumbai, India
• 10 - 20% - primary pediatric
brain tumors (1 . 5 % - 2 . 5 %
adults)
• 25% - posterior fossa tumors
• Incidence – 150 - 300 / year
• Mean age - 6.5 - 9 yrs;
Rare<3 yrs
• No predilection gender or race
• No outstanding genetic
inheritance
• No sufficient data - Geographic
propensity
• No specific risk factors -
Environmental or infectious
• DPGs - most commonly seen BSGs
in the pediatric population and
represent approximately 60% to 75% of
these tumors
16. SIGNS AND SYMPTOMS
• Typically, a combination of cranial nerve
dysfunction and long-tract signs is
considered suggestive of a brainstem lesion
17. • Clinical behavior and presentation highly variable –
Depends on location, growth pattern, age etc
• Symptom evolution reflects aggressiveness
• Insidious course , Gradual evolution = LOW-GRADE
TUMORS
• Shorter and more abrupt onset = HIGHER GRADE TUMORS
• NONDIFFUSE GLIOMAS
- Low grade lesions ; slow growth
- Insidious onset and may not be readily appreciated
• Careful history
• DIPG
• High grade
- Short prodrome of symptoms
- 1-2 months or shorter
18. • Pattern of symptoms reflects the extent of the tumor
• DIPG
- Multiple and bilateral cranial neuropathies
- Long tract signs and ataxia
- Hydrocephalus uncommon initially
• NONDIFFUSE GLIOMAS
- Isolated cranial neuropathies
- Signs and symptoms of increased intracranial
pressure, and ataxia
- Hemiparesis – Rare
19. • Cranial neuropathies are common in most
tumors of the brainstem
- Simultaneous involvement of multiple
cranial nerves = DIPG
- Focal lesions - Limited cranial nerve
involvement
• Upper brainstem - Oculomotor deficits
• Pons – VI, VII
• Lower brainstem - Lower cranial nerve
involvement (Changes in voice, dysphagia and/or
aspiration pneumonias)
20. • Long tract signs (motor dysfunction and
hyperreflexia) - Diffusely growing tumors / Focal
tumors of CMJ
Long tract signs - Conspicuously absent with
dorsal exophytic gliomas
• Ataxia - Loss of proprioceptive sensation, CN VIII
involvement and/or invasion of cerebellar
peduncles, Frequent in DIPG
• Obstructive hydrocephalus – Usually first
sign in focal tectal gliomas (compression of
cerebral aqueduct); In dorsal exophytic gliomas
(Grow dorsally into 4th ventricle)
• Failure to thrive - Infants (CMJ - swallowing
difficulties)
21. Diffuse Pontine Glioma
• Classic triad
1. Cerebellar dysfunction - 87%
2. Multiple lower cranial nerve palsies - 77%
3. Motor paresis and sensory changes (long-tract involvement) – 53%
• Diagnosis on a clinical basis alone
• The extent and duration of symptoms – Less than expected
• Relatively short, 94% - Less than 6 months
• Duration of symptoms
- Predictor of outcome
- Better outcome 6 months or longer
- Worse outcome 1 month or less
22. Diffuse Pontine Glioma
• Most commonly affect VI, VII, IX, and X, and most have diplopia
• Isolated cranial nerve palsy of longer duration (VII) - Better outcome
and longer survival
• Other clinical signs
Cerebellar peduncles – Ataxia (truncal or appendicular)
Long tracts/cerebral peduncles – Hemiparesis, rarely sensory changes
• Obstruction of the fourth
ventricle is rare!
• Hydrocephalus – 20%
• But frequent at the time of tumor progression
23. Tectal Glioma
• Hydrocephalus (aqueductal
stenosis)
• Classic Parinaud syndrome is
not common
• Most have had a long standing history of headaches
and on occasion “clumsiness” or ataxia
• Oculomotor palsy – rare
• Macrocephaly
• Rapidly progressive symptoms - Atypical or more
aggressive tectal gliomas (tend to occur in younger patients)
24. Focal Tumors
• Anywhere in brainstem
• Symptoms reflect the involved anatomic structures
• MIDBRAIN lesions
1. Hydrocephalus
2. Focal neurological deficits
• PONTINE lesions
1. Isolated facial palsies
2. Long-tract signs
3. Hearing loss
• MEDULLA OBLONGATA
1. Lower cranial nerves palsies
2. Respiratory difficulties (including apnea)
3. Recurrent upper respiratory tract infections and pneumonia, and
swallowing difficulties with aspiration of food and saliva
4. In infants
- Failur e to thr iv e
- Gag r eflex affec ted
- Tongue as y mmetr y.
25. Exophytic Tumors
• Difference - only BSG originating from
subependymal glia in the floor of
the fourth ventricle and growing
posteriorly, thereby filling the fourth ventricle
• Only ~ 10% of tumor mass growth occurs
in the brainstem - spared for a long time,
very gradually progressive symptoms
• Careful history - initial symptoms >1 year
• Hydrocephalus – 4th ventricle obstruction not
uncommon
- Intractable vomiting and failure to thrive in infants
- headaches, vomiting, and ataxia in older children
• Papilledema and torticollis - ICP & chronic
tonsillar herniation
26. Cervicomedullary Tumors
• Two clinical syndromes , depending on location of these
tumors at the junction between the medulla and cervical
spinal cord
1. Tumors arising in the medulla
Lower cranial nerve dysfunction Failure to
thrive, dysphagia, dysarthria and dysphonia, chronic upper
respiratory tract infections and aspiration, and sleep apnea
2. Tumors arising in the cervical spinal cord
• Neck pain, torticollis, and sensorimotor deficits in limbs or
cervical myelopathy with weakness and spasticity
Cranial nerve palsies are not typically encountered
• Hydrocephalus - Obstruction the fourth ventricle outlets
• The average duration of symptoms is 2.1 years (slowly
progressive and low-grade nature)
27. Cervicomedullary Tumors
• Similar to intramedullary spinal cord gliomas
• MRI – Delineates rostral and caudal pole; Identify syrinx
or cysts.
• Majority = Benign low grade astrocytomas
• Almost no infiltrative capacity and as a
consequence their growth is limited rostrally by
the decussating white matter tracts of the
corticospinal tract and medial lemniscus
which act as a barrier for further rostral growth
• Medullary tumors - Confined by the decussating fibers
and expand within the medulla, pushing the motor tracts
and nuclei peripherally
• Only high grade tumors with an infiltrative capacity grow
rostrally
28. BRAIN STEM GLIOMAS
Oguz <;ataltepe. M.D ..*. Ahmet <;olak.M.D..*.
Tunc;alp Ozgen. M.D..**. Aykut Erbengi. M.D..**.
Department of Neurosurgery. Faculty of Medicine.
Hacettepe University
Adult Brainstem Gliomas
GERMAN REYES-BOTERO,a,d,e,f KARIMA
MOKHTARI,b,d,e,f NADINE MARTIN-
DUVERNEUIL,c JEAN-YVES
29. • Gait disturbances. headache and
motor weakness were the most
common symptoms
• The most common finding was
cranial nerve involvement (90.3 %)
• Sixth and seventh nerve
involvement were the most
common; occurring in over 69 % of
cases.
• Nystagmus, evidence of cerebellar
disorders and pyramidal tract signs
were frequent manifestations
• Distinct from other tumour in that
they do not cause raised
intracranial pressure early in the
course of the disease despite all
these neurological signs
• Midbrain gliomas of the tectum
behave as very low-grade
lesions
• Focal tumors of the tectum
(te cta l glioma s ) begin to
cause significant neurological
symptoms when they enlarge
and compress the aqueduct of
Sylvius thereby producing
ob str uctive
hy d r oce p halus
• T e gme nta l tumor s can
present with
hy d r oce p halus and
oculomotor p a r e sis
with or without associated
long -tra ct find ings
31. CT
• Screening tool
- Tumor
- Hydrocephalus, or both
• Cannot delineate the exact location and
extent
32. DPG
1. Diffuse enlargement
of pons(diffuse pontine
hypertrophy)
2. Posterior
displacement of the
fourth ventricle
3. Hydrocephalus (rare)
4. Contrast enhanced images –
Nonhomogeneous
enhancement patterns and
33. • Focal tumors in the midbrain
and tectum
- Missed on CT
- False negative diagnosis
- Late onset aqueductal
stenosis
• Calcifications – Rare;
Implies an atypical BSG
• Single-Photon Emission CT
using thallium 201 –
Accumulation of the
radioactive tracer in the
tumor, which is 90% specific
for a BSG (Not correlated
with tumor grade,
enhancement patterns of
other contrast media, or
35. DPG
• T1
- Hypo to Isointense
- Diffuse enlargement of pons with
indistinct margins
- Underestimate true extent
• T2
- Best appreciated
- Hyperintense
• Characteristically engulf the basilar
artery ventrally
• Contrast enhancement – Variable
- Nonhomogeneous inside or around
the tumor or may be absent altogether
in 1/3
- Limited prognostic value
- Indicative of malignant degeneration
• Dissemination along the CSF
pathways
- 15%
DPG
A - Sagittal T1, showing diffuse enlargement of the pons
B - Sagittal T2
C – Axial FLAIR showing tumor engulfing the basilar
artery ventrally
D - T1 contrast demonstrating irregular enhancement
within the tumor
36. Tectal
tumors
- Infiltrating lesions in
tectal plate
- Poorly delineated
and rarely enhance
- Hypointense on T1
bright on T2
- Size > 2 cm and
enhancement
- Worse outcome
- Suggest an
atypical tectal tumor
Tectal glioma
A - Sagittal T2 (expansion and
hydrocephalus)
B – Axial FLAIR showing infiltrative
lesion
37. Focal lesions
• Better circumscribed
• No edema
• Cystic or solid
• Size and characteristics -
similar on T1 and T2
(because of relative lack of
infiltration and edema)
Isointense
• Enhancement – Variable
(Brightly enhancing if
juvenile pilocytic
astrocytoma)
• Occupy <50% of a
brainstem region
(designation “focal”)
• Most common - Midbrain
and medulla
Focal pontine juvenile pilocytic astrocytoma
A - Axial T1 contrast Well-circumscribed
tumor with cysts
B - Sagittal T1 a focal lesion in the pons
C and D - Axial and sagittal T1 contrast
showing complete resection (5 years)
38. Dorsal exophytic
tumors
• Usually NOT well
delineated from brainstem
& Well demarcated
outside
• Frequently extends to 4th
Ventricle
• Variable enhancement
• Follow the imaging
characteristics of
infiltrating gliomas
- T1 hypo
- T2 hyper
• Grow laterally & ventrally
into the brainstem = HGG
• Growing dorsally into the
Dorsal exophytic and cervicomedullary junction (CMJ)
tumors
A & B – Sagittal and axial T1 contrast of a dorsal
exophytic tumor
C - Axial T1 of CMJ tumor demonstrating a rim of
normal tissue around the tumor
D - T1 contrast showing irregular enhancement
within the tumor
39. Cervicomedullary glioma with dorsal exophytic
component
A, Post-contrast sagittal MRI demonstrates
enhancing mass
B, Post-contrast axial MRI
- Similar in appearance to
infiltrating gliomas
- Evidence of growth in
the medulla and cervical
spinal cord
- Epicenter Foramen
magnum area
- Large exophytic
component
- Obstructing 4th V
outlet
- Located in CP angle,
causing compression
and distortion of lower
CMJ tumors
40.
41. MR Spectroscopy
• Limited - Technical difficulties
Small size of anatomical structures
& Proximity of bone and fatty tissue
of the skull base
• Changes observed using MRS
appear similar to those observed in
supratentorial gliomas
• In the pediatric population, MRS has
been shown to detect progression
(decrease in NAA, elevation of Cho,
and decrease in the NAA/Cho and
Cr/Cho ratios) before radiological or
clinical deterioration
• Retrospective study,
9 adult patients with
brainstem gliomas
(histologically
confirmed in 4
cases) evaluated
with single-voxel
MRS before
treatment
- All = Elevation in the
Cho/NAA ratio from
1.08 to 3.32 (normal
is 0.6–0.8)
- 8 = Elevation in the
Cho/creatine ratio
(range 1.89 –1.01)
- 3 = Elevation in the
lactate signal
• The creatine/NAA
ratio was abnormal
in all patients
because of the loss
of the NAA signal
42. MRI
• MR spectroscopy
- Helpful in distinguishing them from the benign
diffuse pontine enlargements (NF1, Acute
demyelinating encephalomyelitis etc)
• Lesions associated with NF1
- Multifocal
- Frequently extend into the cerebellar
peduncles
- Show contrast enhancement
43. - Differentiate b/w low-grade and high-
grade lesions
- Evaluate response to treatment
- Determine the degree of malignancy
in paediatric population
FluoroDeoxyGlucose PET
44. DIFFUSION TENSOR IMAGING &
WHITE MATTER FIBER
TRACTOGRAPHY
• Differentiate diffuse
brainstem gliomas
(deflected fibers) from
demyelinating disease
(lack of distortion)
• The relationship of sensory
and motor tracts to brain
stem tumors has been
investigated in pediatric
patients
• With further studies and
evolution of this technique for
use in the brain stem, DTI
may play a role in assisting
the treatment planning for
brain stem lesions in adults
46. Diffuse lesions
• Fibrillary infiltrating gliomas
but the histologic grade can vary
considerably
- low grade (37%)
- anaplastic (56%), and
- Glioblastoma (5%)
• The true incidences are not known
because of the low biopsy and
resection rate of these tumors
with a BSG
• Other pathologies
- Pilocytic astrocytoma
- Infantile ganglioglioma
- Ganglioglioma and gangliocytoma
- Primitive neuroectodermal tumor
- Germinoma and non
germinomatous germ cell tumors
- Atypical teratoid-rhabdoid tumor
- Vascular anomalies
cavernous or arteriovenous
malformations
- Hemangioblastomas
- Lesions associated with NF1
- Tuberculomas or other infectious
process
- Abscesses
- Focal inflammatory and
demyelinating lesions
- Metastatic tumors
- Demyelinating processes
- Hematomas
- Infarction
- Lymphoma
- Lipoma
- Acoustic neuroma
49. • Little is known about
the pathobiology
- Low rate of biopsy and
resection
• NF1
- Intrinsic lesions in
brainstem that at least
radiographically
resemble diffuse
BSGs but follow a
more benign course
- Focal lesions –
indolent
50. • Brainstem gliomas are typically astrocytomas
• FOCAL, DORSAL EXOPHYTIC AND CERVICOMEDULLARY
GLIOMAS
- Are usually PILOCYTIC astrocytoma (WHO grade I) and
FIBRILLARY astrocytoma (WHO grade II)
- Other low-grade gliomas with indolent growth such as ganglioglioma are
also seen
• DIPGs
- Majority = ANAPLASTIC astrocytoma (WHO grade III) and
GLIOBLASTOMA MULTIFORME (WHO grade IV) : 70-90%
- Remainder = fibrillary astrocytoma (WHO grade II)
• Later stage - Invasion of adjacent levels of the brainstem and
cerebellar peduncles
• Autopsy - Majority of DIPGs are high-grade and more than 50% have
disseminated within the neuraxis
• Growth of low-grade gliomas typically respect fiber tracts and
pial borders
• In contrast, high-grade gliomas grow and expand without
respecting anatomic boundaries of these surrounding tissues
51. • Tectal gliomas – Majority cause hydrocephalus
• Dorsal exophytic gliomas
- Arise from subependymal glial tissue
- > 90% = Pilocytic astrocytomas that grow along the path of least resistance
- Most extends into 4th ventricle rather than infiltrating the brainstem
ventrally
- Tumors that extend laterally and/or ventrally into the brainstem
are usually more aggressive and of higher grade on pathological
examination
• Cervicomedullary gliomas
- Arise from lower medulla or upper cervical spinal cord
- Most = Low-grade astrocytomas, but gangliogliomas and ependymomas are
also seen
- Tumors with epicenters in the upper cervical cord grow dorsally into the
cisterna magna
- Those with epicenters in the lower medulla grow centrifugally as focal
nodules
- Growth is usually confined rostrally by the white matter of the corticospinal tract and
medial lemniscus
52. LOW-GRADE OLIGOASTROCYTOMA in a 19-year-old man presenting a progressive cerebellar syndrome and dysphagia.
Upper panel: (A, B): Evocative radiologic pattern in magnetic resonance showing a diffuse intrinsic brainstem hypointense
lesion without contrast enhancement as seen in T1 sequences and T2-Fluid Attenuation Inversion Recovery (FLAIR)
(C): Magnetic resonance spectroscopy showing only a mild increase of the choline/N-acetyl aspartate ratio without
lipids/lactates peaks modification (white arrow)
Lower panel: (D, E): Histologic sample obtained after biopsy showing a low-grade glioma with an astrocytic component and
oligodendroglial differentiation
(F): Immunohistochemistry showing a low MIB-1 proliferation index.
Adult Brainstem Gliomas
GERMAN REYES-BOTERO,a,d,e,f KARIMA MOKHTARI,b,d,e,f NADINE MARTIN-DUVERNEUIL,c JEAN-YVES DELATTRE,a,d,e,f FLORENCE LAIGLE-
DONADEYa,d,e,f aService de Neurologie 2-Division Mazarin, bService de Neuropathologie, and cService de Neuroradiologie Groupe Hospitalier Pitie´-
Salpeˆtrie`re, APHP, Paris, France; dUniversite´ Pierre et Marie Curie-Paris 6, Centre de Recherche de l’Institut du Cerveau et de la Moelle epiniere,
53. facial paresthesia.
Upper panel: (A): Magnetic resonance image showing a hyperintensity in T2 sequences involving the pons.
(B): T1-weighted sequence showing a contrast-enhanced pontine tumor with “ringlike” pattern. (C): Magnetic
resonance spectroscopy showing an increase in Cho peak and notable reduction in Naa (Cho/Naa 3.5)
Lower panel: (D, E): Histologic sample obtained after biopsy showing a microvascular proliferation (black
arrow) and diffuse expression of glial fibrillary acidic protein. (F): Immunohistochemistry showing a high MIB-1
proliferation index.
Adult Brainstem Gliomas
GERMAN REYES-BOTERO,a,d,e,f KARIMA MOKHTARI,b,d,e,f NADINE MARTIN-DUVERNEUIL,c JEAN-YVES DELATTRE,a,d,e,f FLORENCE LAIGLE-DONADEYa,d,e,f
aService de Neurologie 2-Division Mazarin, bService de Neuropathologie, and cService de Neuroradiologie Groupe Hospitalier Pitie´-Salpeˆtrie`re, APHP, Paris,
France; dUniversite´ Pierre et Marie Curie-Paris 6, Centre de Recherche de l’Institut du Cerveau et de la Moelle epiniere, UMR_S975, Faculte´ deme´decine site Pitie´-
54. Fibrillary Astrocytoma
• Most common
• Grading is difficult - issue of sampling and relative rarity of specimens
• Predominantly composed of fibrillary
neoplastic astrocytes with nuclear atypia
• Mitotic activity (Ki-67/MIB-1 labeling index) is usually < 4%
• Necrosis and microvascular proliferation - can be present
• Molecular characterization
- commonly shows TP53 mutations (>60%), not a predictor of
outcome
- loss of heterozygosity of 22q (1/3)
• The cytogenetic abnormalities of diffuse BSGs resemble those of adult malignant
gliomas
- TP53 mutations
- Mutated epidermal growth factor receptor
genes
55. Pilocytic Astrocytoma
• Cytogenetic analysis - Normal karyotype in
majority
• Focal brainstem lesion
- most often pilocytic astrocytomas
- pathologically do not show any difference
56. Pilocytic Astrocytoma
• Pilocytic astrocytomas with NF1 - genetically
distinct
- loss of normal NF1 expression
- Ras activation, and
- hyperactivation of the mTOR (mammalian
target of rapamycin) pathway
• Less aggressive than non-NF1 lesions
• Difference from diffuse fibrillary astrocytomas
- altered and increased activation of immune response genes
- higher content of proliferating Microglia
57. Ganglioglioma and Gangliocytoma
• Chromosomal abnormalities - 1/3
• gain of chromosome 7 - most common
alteration
• 3 patients had adverse outcomes when
chromosomal abnormalities were present
• Anaplastic changes and high MIB-1 and
TP53 labeling indices - more aggressive
behavior
58. Atypical Teratoid/Rhabdoid Tumor
• First described in 1985, common in the
infratentorial compartment and brainstem
in children younger than 6 years
• Mutation or loss of the INI1 locus on
22q11- typical chromosomal abnormality
of ATRT
• Age > 3 years at diagnosis - Longer
survival (more aggressive therapies)
60. • DBSG - Will not benefit from surgical
intervention
• Focal BSG - Amenable to surgical
resection
• Dorsal midbrain tumors (tectal gliomas)
- Indolent and stable clinically and radiographically for
many years
- Initially managed in a nonoperative manner with
serial imaging
- Surgery is performed in cases of tumor progression on
MRI
- Obstructive hydrocephalus ETV
66. Surgical anatomy - Dorsal
aspect
• Three parts
- Superior / pontine
- Intermediate /
junctional
- Inferior / Medullary
part
67. DPG
• Fatal 6 to 24 ms after diagnosis / treatment & 3 to 6 m
after local progression
• Median survival - 10 months, 13% survive 3 years
• Systemic metastasis – rare
• Leptomeningeal disease - 30% of patients after relapse
• low rate of surgical intervention
- Poor outcomes
- Characteristic radiographic appearance on MRI
- Past surgical morbidity
• This is in contrast to focal, exophytic, and cervicomedullary tumors, which are
amenable to surgical resection
68. Biopsy
• Limited role
- Prognosis is not related to its histologic grade
- Management is mostly independent of the histology of the tumor
Biopsy not indicated when imaging features are
characteristic of DPG
Indication for biopsy
• Atypical features (prognosis and outcome not significantly affected)
• Some of the focal or exophytic lesions
Techniques
- Open biopsy
- Stereotactic biopsy (either frameless or fixed)
• Stereotactic biopsy
- 6% to 11% morbidity rate
- Transient and permanent morbidity rates- 5.6% and 1.4%
70. • Since 1970s
• 5% to 12% of all brain
biopsies
• Not used widely in the
pediatric population
(characteristic MRI -
sufficient to diagnose
DBSG)
• Reported rate of
complications = 2.5% -
7.7% (published series)
• Adults - contrast-
enhancing brain stem
lesions ?? -
Radiographic Diagnosis
incorrect in 10%-25%
(over 20 yrs age )
• Heterogeneity - Difficult to
make a diagnosis on the
basis of imaging alone
• Indicated in many adult
brain stem lesions that
- Enhance with contrast
- Diagnosis of the lesion is
71. • Image guidance - CT or MRI
• Approaches - Depending on the location
1. TRANSFRONTAL - Frequently requires traversing the
lateral ventricle and is limited to midline regions of the
pons and medulla by the tentorial incisura
2. TRANSTENTORIAL - Not used routinely; places vital
vasculature and cranial nerves at risk; cause pain with
tentorial puncture; crosses the pia two additional times
above and below the tentorium
3. TRANSCEREBELLAR - Lesions in the lower midbrain, pons,
middle cerebellar peduncle, and rostral medulla;
intubation and GA generally required (patient
positioning); Discomfort associated with muscle dissection
prior to placement of the twist drill hole
72. • An alternative
CONTRALATERAL,
TRANSFRONTAL,
EXTRAVENTRICULAR
APPROACH using a
Leksell stereotactic
frame system
described for reaching
lesions in the lateral
pons and middle
cerebellar peduncle
• The needle’s trajectory
crosses only one pial
surface and avoids the
ventricle and
tentorium
• In a reported series of six patients,
diagnostic samples were obtained
in all patients and there was no
surgical morbidity
Illustration depicting the
contralateral, transfrontal,
extraventricular approach to an
infratentorial lesion with the aid
of a Leksell stereotactic frame
system
73. Diffuse glioma is an infiltrative,
highly aggressive lesion which
is always malignant regardless
of the histology at the time of
biopsy, associated with a very
poor prognosis, MR
appearance is reliable → No
role of biopsy for these lesions
(Epstein,McCleary,1986)
No role of open
surgery/stereotactic
biopsy in diffuse
tumor because of
typical MRI
characteristics and
clinical presentation (
Isamat, 1999)
Risks of biopsy far
outweigh the
remote possibility
of diagnosing
something other
than a glioma
Majority of focal, dorsally
exophytic and cervicomedullary
BSG are benign and resectable
by direct surgery with low
morbidity and good outcome
New york symposium on
Brainstem surgery, 1996 ;
Epstein, Constantini ,Hoffman, A
Bricolo
• Reserved to
-When the diagnosis is uncertain, to rule out inflammatory pathology like
TB
-Focal intrinsic endophytic lesion - well limited masses within the brainstem
surrounded by neural tissue and therefore do not reach the surface
74. Surgery
• Role in the management of all BSGs but DPG
• Location requires careful planning
preoperatively to minimize surgical morbidity
• Preoperative CSF diversion - Not necessary in
majority
- Exceptions Tectal tumors (hydrocephalus -
initial & frequently sole symptom)
- No need for biopsy of tectal tumors, and the
treatment recommended for hydrocephalus is
endoscopic third ventriculostomy
75. • Adjuncts to surgery -
Essential in focal tumors
- Laser treatment (Nd-YAG
laser)
- Intraoperative monitoring
- Ultrasound and navigation
• Brain stem auditory,
somatosensory, and
motor-evoked potentials
- Monitor their
corresponding pathways
- Does not help to prevent
the injury (functional
mapping is not taking
place)
76. FUNCTIONAL MAPPING
- Responses from muscles innervated by cranial nerves VII, IX, X, and
XII
- Stimulates the floor of the fourth ventricle with a hand-held monopolar
probe
- Tip of the probe = Round & 0.75 mm
- Muscle action potentials (EMG) - Orbicularis oculi and oris
muscles (CN VII), posterior pharyngeal wall (CN IX, X), and
tongue muscles (CN XII)
- Muscle relaxant X
- Threshold intensity = 0.2 Ma (hematoma) - 2.0 mA (tumors)
- Moving the stimulation probe every 1 mm
• No impulses Technical problems / cranial nerve motor nuclei is
ventral to the pathology
• If ventral - Repeated stimulation through the lesion
77. Focal
• Intraoperative navigation
with a frameless system
(MRI) & operating
microscope = Essential
• Approached in the most
direct path, sometimes
guided by bulging or a
small area of
discoloration that is
visible through the pia
• Intraoperative ultrasound
- Ascertaining amount
resected
- Localization for
placement of catheters
in the cystic components
• Intracystic catheters
have been implanted for
- Repeated aspiration of
tumor-related cysts
- Deliver therapeutic
agents (radioactive
sources,
chemotherapeutic
agents)
78. Focal
• Surgical risk - Related to the anatomy and type
- Cystic and pilocytic tumors - Less morbidity
- Solid or infiltrating fibrillary astrocytomas – More
• Goals of the surgery - Clearly thought out and
discussed with the patient and family (benefits and
complications)
• M E D U L L A
- Need for tracheostomy and feeding gastrostomy (
considerable recovery potential in children)
• P O N S A N D M I D B R A I N
- Permanent eye movement problems
- Injury to the long tracts
79. Exophytic
• Midline posterior fossa craniotomy
• No indication to split the vermis
• Elevation of the cerebellar tonsils via a telovelar approach will allow
access to the tumor
• Two types - Warrant different surgical approaches
1. TRUE EXOPHYTIC TUMORS
- Grow primarily outside the brainstem
- Only a very small component that is infiltrating the brainstem
- Floor of the fourth ventricle is identified first and then the tumor is
removed in a stepwise fashion that avoids pursuit of the tumor into
the brainstem itself
2. INTRINSIC BRAINSTEM TUMOR WITH A LARGE EXOPHYTIC
COMPONENT
- Approached by removing the exophytic component capping the
intrinsic component
- It opens a broad pathway into the intrinsic tumor component, which
can be removed by internal debulking and careful dissection at the
margins
80. Cervicomedullary
• Resectable - Infiltration into the medulla
and the cervical spinal cord limit the
extent of resection
• Early surgery - Avoid the late neurological
deficits
• Approached via a midline posterior fossa
craniotomy and possibly a cervical
laminotomy
• Often arises from the floor of the fourth
ventricle, no exophytic component
myelotomy or opening through the floor
of the fourth ventricle
81. Anesthesia for brainstem
surgery
• Multimodal
monitoring – SpO2
& ETCO2
monitoring, CVP
line, arterial line,
trans-esophageal
echocardiography,
etc.
82. Surgical Techniques
• Precise movements & good intraoperative
judgment
• An optimally functioning surgical
microscope
• Intrinsic tumors
- Incision in the surface of the brain stem;
require a thorough understanding of the
anatomy
- Many tumors can be accessed where it is
closest to the surface (Not always the rule)
- Incision small and less than 1 cm
- Tumors in the vicinity of the corticospinal
tracts in the cerebral peduncles, fourth
ventricular floor – M a p p i n g
83. Surgical Techniques
• Dorsal pontine tumors approached through the
fourth ventricular floor can be entered through
the
- median sulcus above the facial colliculus
- suprafacial, infrafacial, and area acoustica
• Tectal mesencephalic
- Supracollicular, infracollicular, and lateral
mesencephalic sulcus
• Medullary and cervicomedullary tumors
- Longitudinal myelotomies in the posterior
median fissure below the obex, posterior
intermediate sulcus, and posterior lateral sulcus
84. Tumour decompression
• Consistency determines the method of
extirpation (piecemeal fashion= solid / Suction &
aspiration= soft)
• Frozen section determines amount of extirpation
• Conventional suction technique frequently causes
brainstem dysfunction manifested by bradycardia
& arrhythmia
• CUSA causes movement of adjacent structures
only within 1mm of vibrating tip, allowing for
extensive and quick dissection adjacent to or
within the substance of brainstem
• Cyst - Aspiration / Debulking early
• Tumor resection should be stopped when an
interface between the two cannot be visualized
85. Surgical technique-
Focal tumour
• Use of plated
bayonet(very small
plates at the tip) as
‘microretractor’
• CUSA at a low setting
• Careful identification
of white matter
interface
• Minimal manipulation
of adjacent normal
tissue
86. Surgical technique-
Cervicomedullary tumor
• Suboccipital craniotomy
+ osteoplastic
laminotomy
• Expose both rostral and
caudal extent of the
tumor
• USG guidance to know
extent of tumor prior to
opening the dura -
entire tumor should be
within the confines of
the operative exposure
87. Surgical technique- Cervicomedullary tumor
• The rostral end of a benign
cervicomedullary tumor
invariably expands
posteriorly at the obex
• Tumor is, in fact,
displacing the medulla
rostrally rather than
extending into it
• This explains why these
tumor present with cervical
myelopathy rather than
LCN dysfunction
• Conceptually, these tumor
should be regarded as ‘
intramedullary spinal cord
tumors’
• Tumor is approached from
within its center
88. Surgical technique-
Cervicomedullary tumor
• Midline myelotomy
- ‘True’ midline to be
identified
- Identify DREZ bilaterally
• If tumor is solid-cystic,
myelotomy to be placed
first at tumor –cyst
junction and cyst is
removed prior to tumor
excision
• If tumor is non-cystic,
myelotomy where tumor
is most voluminous &
closest to the pial surface
89. Surgical technique-
Cervicomedullary tumor
• Myelotomy to be
terminated 1 cm
proximal to the caudal
pole of the tumor →
tumor is least
voluminous here,
removed by gradual
upward dissection
• At the rostral pole,
tumor invariably subpial
and bulging posteriorly
at the obex
90. Surgical technique-
Cervicomedullary tumour
• USG to guide the extent of tumor excision-
to confirm bulk of tumor is removed
• Don’t chase small questionable fragments
• If deterioration of SSEP/MEP during the
procedure, interrupt the dissection and
move to another area
91. Peri-operative care
• Perioperative steroids( methylprednisolone)
• Elective ventilation for at least 48 hours
• Mechanical ventilation till recovery of
ventilation & normal cough reflex
• LCN paresis - NG/feeding gastrostomy
• V,VII nv paresis - temporary tarsorrhaphy
• Good nursing care
• Physiotherapy
• Post-op brainstem injury mostly reversible if
surgical technique is proper
92. Adjuvant Therapy
• Corticosteroids - Earlier improvement in symptoms than with
other interventions
• RT
- Standard of care for DIPG
- Not recommended as an early treatment for nondiffuse brainstem
gliomas if pathology shows a low-grade glioma
- Usually used in patients with high-grade pathology, upon clinical and
imaging evidence of progression, or late in the disease course
• Stereotactic radiosurgery is also used in nondiffuse
brainstem gliomas
• Chemotherapy
- Limited use in the management of brainstem gliomas
- Mainly used for high-grade pathology or at late stage of the disease
94. DIPG
• Established role in the management of BSG
• Standard treatment of DIPG - Alone or in
combination with chemotherapy(before, during, or
after completion of RT)
• The standard of care for DIPG is involved field
external beam radiation therapy, typically
delivered at 1.8Gy/fraction for 30-33 fractions
• Most DIPGs responded well to radiation with often
dramatic improvement in the scan and clinically
• However 90% died by 2 years and less than 2%
survived on long term follow-up
• Median survival only 9 to 10 months
Even with Direct RT + CT <10% will survive 2 years
95. Focal gliomas
• Conventional RT - Limited efficacy
• High-grade tumors
- After recovery from surgery
- When surgery is not indicated
• Low-grade tumors may be observed and treated only if there is
subsequent tumor progressio
• Implantation of iodine-129 (I-129) or iodine-125 (I-125) seeds has
been used in some patients with acceptable tumor control
• I-125 is an alternative to resection, external beam radiation
therapy and chemotherapy in children with progressively
symptomatic low-grade gliomas in deep and eloquent areas
where high postoperative morbidity would be expected with
open surgery
• Stereotactic radiosurgery has been used as an alternative
means for managing focal brainstem gliomas
• Its use has been reported in patients with progressive tumor
growth or worsening neurological deficits.
96. Dorsal exophytic gliomas
• Inoperable tumors
• Recurrent disease not amenable to re-
resection
• Treatment primarily consists of
conventional external beam radiation
therapy with 30-33 daily fractions of
1.8Gy/fraction
• Use of stereotactic radiation therapy
and radiosurgery has also been
examined in small cohorts
97. Cervicomedullary gliomas
• Surgery is typically the initial treatment
modality
• RT reserved for
- Advanced diseases
- Recurrent diseases not amenable to
surgical resection
• Conventional fractionated external beam
radiation given at 1.8Gy/fraction for 30-33
fractions
• Stereotactic radiation therapy and
radiosurgery has also been examined in
small cohorts
98. Radiation Therapy
ADULT DIFFUSE INTRINSIC LOW-GRADE BRAINSTEM GLIOMA
• Standard treatment ; can improve or stabilize patients for
years
• Conventional median dose = 50–55 Gy (Fractions of 1.8–2
Gy)
• Clinical improvement occurs in the majority
• Reports of Substantial discrepancy between the clinical and
radiological response
• 48 adult patients (including 46% of intrinsic diffuse gliomas),
radiotherapy
- Improved clinical status in 61%
- Partial radiological response (a decrease of 50% in the T2
hyperintensity in the greatest axial cross-sectional area) was noted in
only 19%
• Specific criteria to evaluate tumor response to treatment
in brainstem gliomas could be different than the criteria
used for supratentorial glioma
• The optimal time of treatment remains unknown
• Some patients may have mild symptoms during extended
periods without any treatment - Radiotherapy may
99. Radiation Therapy
ENHANCING MALIGNANT BRAINSTEM
GLIOMAS
• Malignant brainstem gliomas are highly
resistant to treatment by radiotherapy
• Only 13% (2 out of 15 patients) showed
clinical and radiological improvement
• Gamma knife radiosurgery has been
reported in some cases of high-grade
brainstem gliomas, but the published
data are limited and preliminary
100. • FOCAL TECTAL BRAINSTEM
GLIOMAS – No role
• Associated with longer
median survival
(exceeding 10 years)
following
ventriculoperitoneal
shunting and in some cases
focal radiotherapy
• EXOPHYTIC
BRAINSTEM
GLIOMAS –
No role
Hamilton MG, Lauryssen C, Hagen N. Focal
midbrain glioma: long term survival in a cohort of 16
patients and the implications for management.
Can J Neurol Sci 1996;23:204 –207
Bowers DC, Georgiades C, Aronson LJ et al. Tectal
gliomas: natural history of an indolent lesion in
pediatric patients
Pediatr Neurosurg 2000;32:24–29.
101. Radiation Therapy
• Chemotherapy before RT - No survival
benefit
• Temozolomide after RT - Efficacious for
high-grade gliomas, but did not alter the
poor prognosis associated with newly
diagnosed DPG in children
• Dose escalation and hyperfractionation -
Not shown evidence of dose-dependent
improvement of the 2-year survival rate
(3% to 21%) and of median survival (9 to 13
months)
102. Role of GKRS
• 20 patients
• 10-18 Gy
• Median follow up- 78 months
• Tumor disappeared in 4 pts,
decreased in size in 12 pts
• Minimal peri & post-
procedural morbidity
• Currently, there is no role
for stereotactic
radiosurgery in the
management of DPG
• Stereotactic RT, either
fractionated or single
dose, can be very
effective for the treatment
of
Recurrent or residual
low-grade focal or
infiltrative tumors that are
unresectable or have
failed chemotherapy
Yen CP, Sheehan J, Steiner
M, Patterson G, Steiner L.
Gamma knife surgery for
focal brainstem gliomas.
J Neurosurg. 2007
Jan;106(1):8-17.
105. DIPG
• Various chemotherapeutic
regimens have been
studied either alone or in
combination with
radiation therapy
• Up to date, no
chemotherapeutic agent,
either alone or in
combination, or in
conjunction with radiation
therapy, has altered the
natural history of DIPG
• Many patients are
enrolled in clinical trials of
new agents or previously
used agents in previously
untested combinations
• Response rates – up to 15%
to 20%
• No survival benefit
• Various regimen -
cyclophosphamide,
carboplatin, cisplatin,
etoposide, and thiotepa,
some in combination with
blood-brain barrier
disrupting agents
• Metronomic therapy
- Continuous low-dose
chemotherapy
- Block mechanisms
stimulating the growth of
new blood vessels needed
to feed the tumor
- Promising results in the
management of gliomas
(no significant effect on
DPG)
106. Other BSGs - follows the same principles
as for gliomas in other locations in the
central nervous system
107. FOCAL GLIOMAS
• Role not been well evaluated
• In general, for tumors that total or
subtotal resection has been performed on
and subsequently progress, chemotherapy
may be considered with or without
radiation therapy
• In children younger than 3 years old,
chemotherapy may be used alone in
attempts to delay the need for radiation
therapy
109. • Cytotoxic chemotherapy, including the newest
agent temozolomide is not effective and the
recently introduced targeted therapies with
imatinib mesylate, gefitinib, erlotinib, and
antiangiogenic therapy did not produce better
results
• Multitargeted therapy with antineoplastons
A10 and AS2-1 (ANP), currently in clinical trials,
has produced encouraging results in newly
diagnosed DBSG
• New strategies employing multitargeted
approach may offer better results in the future.
110. Combination Therapy
• A Pediatric Oncology Group study
- No significant difference between hyperfractionated irradiation
with 78 and 54 Gy in conventional one-per-day fractions
combined with cisplatin
- Combining hyperfractionation with interferon beta therapy had
a more benign side effect profile but failed to change survival
• Combinations with radiosensitizers
- No combination has demonstrated more benefit than RT has
alone
• An aggressive therapy scheme
- Toxic in a series of 11 patients
- Long-term objective good outcomes in more than 50% of
patients with histologically confirmed DPG and dorsal
exophytic BSGs
111. PROGNOSIS AND
OUTCOMES
• Two radiographic features provide the most useful prognostic
information : epicenter of the tumor and diffuseness
• 5-year survival rate
- Focal tumors - 75% and 65% (midbrain and medulla
respectively)
- DPG – 18%
- Focal tumors - 70%
- Diffuse tumors - 22%
- Other studies - lower 3-year survival rates of 10%
• Preoperative symptoms such as upper respiratory tract
infections, pneumonia, and voice alterations were associated
with postoperative ventilator dependency
• Preoperative swallowing difficulties - correlated closely with
the need for a feeding gastrostomy postoperatively
112. SUMMARY
The DIPG “ranks first
amongst pediatric brain
tumors with a poor
prognosis.”J. Neurosurgery
Peds 3:257-258, 2009
113. Epstein & Farmer Classification
1. DIPG (80%)
2. Focal Tumors (5%)
a) Tectal tumors
b) Pontine tumors
c) Midbrain tumors
3. Dorsal exophytic tumors(10 -15%)
4. Tumors of the cervicomedullary junction
(CMJ) 5 -10%
• Thalamic tumors - considered some authors
• CMJ tumors - considered by most to be a subgroup of BSGs, although some
clinicians believe that they are the most cephalic extension of cervical
intramedullary spinal cord tumors
114. • MIDBRAIN (7 - 8%)
- Almost always low-grade pilocytic astrocytomas (WHO I & II)
- Good prognosis
• PONS (80 %)
- Usually High grade astrocytomas (WHO III & IV)
- Dismal prognosis
• MEDULLA (10 - 15%)
- Usually low grade pilocytic astrocytomas (WHO I & II)
- Good to fair prognosis
115. • FOCAL, DORSAL EXOPHYTIC AND
CERVICOMEDULLARY GLIOMAS
- Are usually PILOCYTIC astrocytoma
(WHO grade I) and FIBRILLARY
astrocytoma (WHO grade II)
• DIPGs
- Majority = ANAPLASTIC astrocytoma
(WHO grade III) and GLIOBLASTOMA
MULTIFORME (WHO grade IV) : 70-90%
- Remainder = fibrillary astrocytoma (WHO
grade II)
• Growth of low-grade gliomas typically
respect fiber tracts and pial borders
116. • Symptom evolution reflects aggressiveness
• Low-grade tumors - Insidious course over several
months of gradual symptom progression
• Shorter and more abrupt onset = Higher grade
tumors
• Pattern of symptoms reflects the extent of the
tumor
• DIPG
- Multiple and bilateral cranial neuropathies
- Long tract signs and ataxia
- Hydrocephalus uncommon
• NONDIFFUSE GLIOMAS
- Isolated cranial neuropathies
- Signs and symptoms of increased intracranial
pressure, and ataxia
117. Tumors arising in the medulla
Lower cranial nerve dysfunction
Failure to thrive, dysphagia, dysarthria
and dysphonia, chronic upper respiratory
tract infections and aspiration, and sleep
apnea
2. Tumors arising in the cervical spinal cord
• Neck pain, torticollis, and sensorimotor
deficits in limbs or cervical myelopathy
myelopathy with weakness and spasticity
Cranial nerve palsies are not typically
encountered
118. • Long tract signs (motor dysfunction
and hyperreflexia) - Diffusely growing
tumors / Focal tumors of CMJ
Long tract signs - Conspicuously
absent with dorsal exophytic gliomas
• Obstructive hydrocephalus –
Usually first sign in focal tectal gliomas
(compression of cerebral aqueduct)
119. • Mutation of P53, a tumor suppressor
gene
• Amplification of mutated EGFR gene
• Trisomy 1q, deletion of chr 19
• NF 1 More indolent course
120. CONCLUSION
• MRI and PET : Commonly used, it does not
accurately replace histological diagnosis
• DIPG – RT + CT
• For BSG with NF1 , no treatments are
recommended unless there is rapid tumor
growth and symptomatic worsening in the
patient’s condition (Pollack et al, 1996; Guillamo
et al, 2001)
• Therapy for focal, dorsal exophytic and
cervicomedullary tumors is similar to other
types of primary brain tumors (Freeman and
Farmer, 1998)
121. CONCLUSION
• The determination of frequency of
histopathologic types is not accurate, since
only approximately 25% of these patients
have a biopsy
• Autopsy results confirm that the majority
are high-grade gliomas, usually anaplastic
astrocytomas (AA) (Freeman and Farmer,
1998)
• Glioblastoma multiforme (GBM) and low-
grade, or grade 2 astrocytoma, occur in
lesser frequency
122. CONCLUSION
• Stereotactic biopsy : Since the pathology diagnosis
is difficult to obtain, dangerous and misleading,
diagnosis based on MRI is the standard of care
(Freeman and Farmer, 1998)
• Reserved to many adult brain stem lesions that
- Enhance with contrast & When the diagnosis is
uncertain, to rule out inflammatory pathology like
TB
- Focal intrinsic endophytic lesion - Well limited
masses within the brainstem surrounded by neural
tissue and therefore do not reach the surface
123. • Dorsally exophytic tumor
- Likely to be benign
- Radical excision
- Do not enter brainstem
• Cervicomedullary tumor
- Likely to be benign
- Radical excision
• Cystic tumor
- Radical excision
• Focal pontine tumor - Radical excision if tumor
is close to the surface
128. • Uncommon 1%–2% of intracranial gliomas
• Heterogeneous group
• Low grade phenotype predominates(80%)- Better
prognosis
• Longer survival
• Adult diffuse intrinsic brainstem gliomas are low-grade
tumors at the onset in contrast with those in children
where a similar nonenhancing MRI aspect often
indicates a high-grade glioma associated with rapidly
progressive clinical impairment and shorter survival
• Histological proof necessary in many contrast-enhanced
focal brainstem lesions - Wide variety of DD’s
• Diffuse intrinsic low-grade BSG - Conventional
radiotherapy (the median survival is 5 years)
• Malignant BSG - Radiotherapy
• Combined radiotherapy and chemotherapy
(temozolomide or other agents) - Not been thoroughly
evaluated in adults
129. • A biopsy is rarely performed in typical
intrinsic diffuse glioma in adults
• When it is performed, a low-grade
histology (grade II glioma) is found in up to
80% of cases, whereas in children a grade
IV glioma is the most frequent phenotype
reported in 50%–60% of cases
• This feature probably accounts for the
better prognosis of the adult form
MEDULLARY SYNDROMES
1. MEDIAL MEDULLARY SYNDROME (DEJERINE’S ANTERIOR BULBAR SYNDROME)
This syndrome often results from atherosclerotic occlusion of the vertebral artery, anterior spinal artery, or the lower segment of the basilar artery. Vertebrobasilar dissection, dolichoectasia of the vertebrobasilar system, embolism, and meningovascular syphilis are less common causes of the medial medullary infarction. The anterior spinal artery supplies the paramedian region of the medulla oblongata, which includes the ipsilateral pyramid, medial lemniscus, and hypoglossal nerve and nucleus. Its occlusion therefore results in the
following signs:
1. Ipsilateral paresis, atrophy, and fibrillation of the tongue (due to cranial nerve XII affection). The protruded tongue deviates toward the lesion (away from the hemiplegia). Cranial nerve XII function may be spared.
2. Contralateral hemiplegia (due to involvement of the pyramid) with sparing of the face.
3. Contralateral loss of position and vibratory sensation (due to involvement of the medial lemniscus). The more the dorsolateral spinothalamic tract is unaffected, the more the pain and temperature sensation are spared.
4. Occasionally, upbeat nystagmus may occur because of dorsal extension of the infarct toward the medial longitudinal fasciculus.
Unilateral lesions of the nucleus intercalatus can account for primary position upbeat nystagmus due to a unilateral medial medullary infarction [69]. It has also been proposed that damage to the uncrossed climbing fibers from the inferior olivary nucleus to the contralateral cerebellar Purkinje cells results in ocular contra pulsion from rostral medial medullary infarctions [81].
The medial medullary syndrome may occur bilaterally [57,99] resulting in flaccid quadriplegia (with facial sparing), bilateral lower motor neuron lesions of the tongue, complete loss of position and vibratory sensation affecting all four extremities and respiratory failure, or acute onset of triparesis (with involvement of both lower limbs and contralateral upper extremity), suggestive of a possible fiber segregation of the descending tracts of different extremities [58]. Located in the caudal medullary tegmentum, both hypoglossal nuclei have been involved in isolation in a small medullary infarction [12].
Because the hypoglossal fibers run somewhat laterally to the medial lemniscus and pyramid, they are occasionally spared in cases of anterior spinal artery occlusion. Occasionally, only the pyramid is damaged, resulting in a pure motor hemiplegia that spares the face [30,128,135]. Central facial paresis may also result from a unilateral contralateral medullary infarction, suggesting that some of the facial corticobulbar fibers descend ipsilaterally before making a loop as low as the medulla oblongata before decussating and ascending to the
contralateral facial nucleus that innervates the perioral musculature [26,148].
A crossed motor hemiparesis (hemiplegia cruciata), with paralysis of the ipsilateral arm and the contralateral leg (resulting from a lower medullary lesion compromising the crossed fibers to the arm as well as the uncrossed fibers to the leg), is an extremely rare occurrence [14].
Apart from incomplete syndromes (e.g., medial medullary syndrome presenting as pure motor hemiparesis, or medial medullary syndrome without tongue paralysis), other unusual neurologic findings may be observed including contralateral paralysis of the pharyngeal constrictor muscle [111] and contralateral tongue paralysis [27]
2. LATERAL MEDULLARY (WALLENBERG) SYNDROME
This syndrome is most often secondary to intracranial vertebral artery or posterior inferior cerebellar artery occlusion
The presumed pathogenesis among 130 consecutive patients with pure lateral medullary infarctions included large vessel disease in 50%, arterial dissection in 15%, small vessel disease in 13%, and cardioembolism in 5%
Spontaneous dissections of the vertebral arteries are a common cause
Dissections were observed more often with caudal lesions
The syndrome has also been described with cocaine abuse , medullary neoplasms (usually metastases), abscess, demyelinating disease , radionecrosis, hematoma (secondary to rupture of a vascular malformation), neck manipulation , trauma, bullet injury to the vertebral artery , and posterior spinal fusion surgery with instrumentation in a patient with a previously undiagnosed Chiari 1 malformation . The characteristic clinical picture results from damage to a wedge-shaped area of the lateral medulla and inferior cerebellum and
consists of several signs:
1. Ipsilateral facial hypalgesia and thermoanesthesia (due to trigeminal spinal nucleus and tract involvement). Ipsilateral facial pain is common.
2. Contralateral trunk and extremity hypalgesia and thermoanesthesia (due to damage to the spinothalamic tract).
3. Ipsilateral palatal, pharyngeal, and vocal cord paralysis with dysphagia and dysarthria (due to involvement of the nucleus ambiguus).
4. Ipsilateral Horner syndrome (due to affection of the descending sympathetic fibers). Ipsilateral hypohidrosis of the body may occur, probably due to interruption of the mostly uncrossed excitatory sweating pathway, which descends from the hypothalamus through the tegmental area of the mesencephalon and pons and, more caudally, through the posterolateral area of the medulla to synapse with the sympathetic sudomotor neurons of the intermediolateral cell column of the spinal cord.
5. Vertigo, nausea, and vomiting (due to involvement of the vestibular nuclei).
6. Ipsilateral cerebellar signs and symptoms (due to involvement of the inferior cerebellar peduncle and cerebellum).
7. Occasionally, hiccups (singultus) attributed to lesions of the dorsolateral region of the middle medulla [117] and diplopia (perhaps secondary to involvement of the lower pons).
Lateral lesions located in the rostral medulla are associated with more severe dysphagia, hoarseness, and the presence of facial paresis, whereas more caudal lesions situated in the lateral surface of the medulla, correlate with more marked vertigo, nystagmus, and gait ataxia . Nausea, vomiting, and Horner syndrome are common regardless of the location of the lesion in the lateral medulla; lesions that extend more ventromedially cause facial sensory changes on the contralateral side of the lesion [80]. The motor system (pyramids), tongue
movements, and vibration and position sense are typically spared with lateral medullary lesions because the corresponding anatomic structures are located in the medial medulla. The triad of Horner syndrome, ipsilateral ataxia, and contralateral hypalgesia clinically identifies patients with lateral medullary infarction [132]. Cerebellar infarcts only infrequently accompany the lateral medullary syndrome, suggesting that most of the posterior inferior cerebellar artery territory is spared, despite the high frequency of vertebral artery occlusion as a cause of this syndrome [132].
Headache, especially unilateral headache localized to the upper posterior cervical region, is relatively common with the lateral medullary syndrome, particularly when the syndrome is due to cervical vertebral artery dissection [64,105]. This type of headache should be distinguished from the rare paroxysmal retro-orbital hemicranial-like attacks reported after strokes involving the dorsal medulla and high cervical spinal cord at the C1 level [36].
The sensory defect in the lateral medullary syndrome usually aects the ipsilateral face and the contralateral leg, arm, and trunk. However, several patients with lateral brainstem lesions developed a sensory defect involving the ipsilateral face and the contralateral foot, with the latter defect extending upward to end in a sensory level [96]. These patients with a crossed pattern of sensory defect had far lateral lesions of the lateral medulla and pons, with the leg and lower torso involvement due to selective partial disruption of the somatotopically organized sacral and lumbar aerent bers of the lateral spinothalamic tract (located far laterally in the brainstem), with sparing of the more medial thoracic and cervical bers [96]. Several patients have also been described with a continuous hemisensory defect of the face, arm, and trunk (unilateral pattern), with the lower border demarcated at a sensory level [96]. These patients were thought to have mediolateral medullary and pontine lesions contralateral to the side of the sensory defect, which aected the medial cervical and thoracic aerents of the lateral spinothalamic tract (i.e., spared the lateral sacral and lumbar aerents) and the ventral trigeminothalamic tract (accounting for contralateral facial sensory loss), but spared the spinal nucleus and tract of the trigeminal nerve. In rare instances of infarcts involving the pontomedullary sulcus, sensory symptoms electively involve the contralateral upper limb and base of the neck resulting in loss of pain and temperature, and reinforcing the notion that a somatotopic arrangement of the spinothalamic tract in its medullary course [160].
Rare manifestations of the Wallenberg syndrome include the following:
1. Wild arm ataxia probably related to involvement of the lateral cuneate nucleus [32,33].
2. Clumsiness of the ipsilateral upper limb resulting from extension of the injury into the subolivary area [22
3. Central pain associated with allodynia [121].
4. Contralateral hyperhidrosis with ipsilateral anhidrosis due to interruption of the sympathetic pathways (noted a few months after infarction) [130].
5. An inability to sneeze due to compromise of the sneezing center located at the ventromedial margin of the descending tract and nucleus (spinal nucleus) of the trigeminal nerve.
6. Paroxysmal sneezing due to presumed involvement of the hypothetical human “sneezing center” in the rostral dorsolateral medulla.
7. Loss of taste that results from involvement of the rostral and the lateral zone of the nucleus tractus solitarius [59].
8. Autonomic dysfunction including tachycardia, blood pressure lability, and respiratory failure from the involvement of the caudal and medial zone of the nucleus tractus solitarius .
9. Failure of automatic breathing (Ondine’s curse) due to discrete lesions of the nucleus ambiguus and the adjacent reticular formation.
10. Transient urinary retention from interruption of descending fibers from facilitatory pontine micturition centers [89].
11. Body lateropulsion without limb ataxia from the involvement of the descending lateral vestibulospinal tract, or body lateropulsion with limb ataxia due to interruption of the ascending dorsal spinocerebellar tract [151].
12. Axial lateral pulsion that results from the involvement of the vestibulospinal and spinocerebellar tracts as well as central vestibular pathways [7].
13. Isolated ipsiversive lateropulsion [3].
14. Pure sensory stroke with loss of pain and temperature involving the face, arm, trunk, and leg as the only manifestations of the lateral medullary infarction [8,15].
15. Ipsilateral sensory symptoms predominantly involving the upper extremities, especially the ngers, with occasional impairment of vibration and position sense from caudal lesions involving the dorsal columns or decussating lemniscal fibers [79].
16. Ipsilateral hemiparesis from the involvement of the lower most caudal end of the medulla just below the pyramidal decussation [38]. An ipsilateral spastic hemiplegia associated with a lateral medullary syndrome is also known as the submedullary syndrome of Opalski
17. Central hypoventilation is seen along with vasomotor instability [87].
18. Poststroke facial pain that results from the involvement of the primary afferent fibers in the descending spinal trigeminal tract
Various abnormalities of eye movements and vision have been described with the lateral medullary syndrome. [18,21,29,39,100]. These include the following:
Dysfunction of ocular alignment
Lateral medullary lesions damage the otolithic vestibular nuclei and, therefore, patients with Wallenberg syndrome often demonstrate skew deviation with hypotropia on the side of the lesion [77]. Brandt and Dieterich have called this type 2 skew deviation and stated that this skew results from elevation of the contralateral eye, without vertical displacement of the ipsilateral eye [19,20]. Some patients also show an ipsilateral head tilt and a disconjugate ocular torsion (the ocular tilt reaction, see Chapter 8) with excyclodeviation of the ipsilateral lower eye but with little or no incyclodeviation of the contralateral higher eye [20,39,107]. Therefore, patients may complain of diplopia with images displaced vertically and tilted with respect to each other. Some patients with Wallenberg syndrome may also exhibit ocular ipsipulsion due to damage to the climbing bers from the contralateral inferior olivary nucleus to the dorsal vermis [82] or complain of the unusual (and almost unbelievable) sensation of environmental tilt, in which the whole room is tilted on its side or even upside down (“oor-on-ceiling” phenomenon) [39,127]. This syndrome is also probably caused by a disturbance of vestibular-otolith central connections [127]. Environmental tilt or “upside down” reversal of vision may also occur with vertebrobasilar transient ischemic attacks [143], vertebrobasilar ischemia [144], encephalitis, head injury [100], demyelinating disease [138], or after third ventriculostomy for hydrocephalus [116].
OPALSKI (SUBMEDULLARY) SYNDROME
When ipsilateral hemiplegia is associated with symptoms of a lateral medullary syndrome, it corresponds to the submedullary syndrome of Opalski. Opalski syndrome results from an occlusion of the vertebral artery. The ipsilateral hemiplegia is due to a lesion of the lower medulla involving the corticospinal tract after the pyramidal decussation [71,115].
LATERAL PONTOMEDULLARY SYNDROME
This syndrome [48] may result from occlusion of an aberrant arterial branch arising from the upper vertebral artery and running superiorly and laterally to the region of exit of cranial nerves VII and VIII from the pons. It may also occur with pontine hemorrhage [4]. The clinical findings are those seen in the lateral medullary syndrome plus several pontine findings, which includes the following:
Ipsilateral facial weakness (due to involvement of cranial nerve VII)
Ipsilateral tinnitus and, occasionally, hearing disturbance (due to involvement of cranial nerve VIII)
PONTINE SYNDROMES
VENTRAL PONTINE SYNDROMES
Millard-Gubler Syndrome.
A unilateral lesion of the ventrocaudal pons may involve the basis pontis and the fascicles of cranial nerves VI and VII. This involvement results in the following:
1. Contralateral hemiplegia (sparing the face) is due to pyramidal tract involvement.
2. Ipsilateral lateral rectus paresis (cranial nerve VI) with diplopia that is accentuated when the patient “looks toward” the lesion.
3. Ipsilateral peripheral facial paresis (cranial nerve VII)
Raymond Syndrome.
A unilateral lesion of the ventral medial pons, which affects the ipsilateral abducens nerve fascicles and the corticospinal tract but spares cranial nerve VII, may cause this rare syndrome (also called alternating abducens hemiplegia) , which consists of the following:
1. Ipsilateral lateral rectus paresis (cranial nerve VI)
2. Contralateral hemiplegia, sparing the face, due to pyramidal tract involvement Pure Motor Hemiparesis
Lesions (especially lacunar infarction) involving the corticospinal tracts in the basis pontis may produce a pure motor hemiplegia with or without facial involvement [48,52,101,112]. Patients often have severe dysarthria and dysphagia. Bouts of uncontrollable laughter may also occur [136]).
Other locations of lesions causing pure motor hemiplegia include the posterior limb of the internal capsule, the cerebral peduncle, and the medullary pyramid [30]. A combination of dysarthria and a history of previous transient gait abnormality or vertigo favor a pontine lesion as the cause of pure motor hemiparesis rather than a more common capsular lesion [112].
Dysarthria—Clumsy Hand Syndrome.
Vascular lesions in the basis pontis (especially lacunar infarction) at the junction of the upper one-third and lower two-thirds of the pons may result in dysarthria—clumsy hand syndrome.
In this syndrome facial weakness and severe dysarthria and dysphagia occur along with clumsiness, impaired finger dexterity, and paresis of the hand. Hyperreflexia and a
Babinski’s sign may occur on the same side as the arm paresis, but sensation is spared. A similar clinical presentation may occur with lesions in the genu of the internal capsule or with small, deep cerebellar hemorrhages .
Ataxic Hemiparesis.
A lesion (usually a lacunar infarction) in the basis pontis at the junction of the upper one-third and the lower two-thirds of the pons may result in the ataxic hemiparesis (homolateral ataxia and crural paresis) syndrome.
In this syndrome hemiparesis that is more severe in the lower extremity, is associated with ipsilateral hemiataxia and occasionally dysarthria, nystagmus, and paresthesias. The hemiparesis is also associated with hyperreflexia and a Babinski’s sign. The lesion is located in the contralateral pons.
The ataxia is unilateral, probably because transverse fibers originating from the contralateral pontine nuclei (and projecting to the contralateral cerebellum) are spared [110]. This syndrome has also been described with contralateral thalamocapsular lesions, lesions of the contralateral posterior limb of the internal capsule, lesions of the contralateral red nucleus, and with supercial anterior cerebral artery territory infarcts in the paracentral area [17,67].
As a rare occurrence, focal infarcts in the basilar pons have been associated with dysarthria-dysmetria, dysarthria-facial paresis, or ipsilateral gaze paresis and internuclear ophthalmoplegia [136].
Locked-in Syndrome.
Bilateral ventral pontine lesions (infarction, tumor, hemorrhage, trauma, cervical manipulation, tumor, pontine abscess, encephalitis, arteritis, neuro-Behcet’s, multiple sclerosis, air embolism, heroin abuse, diazepam toxicity, or central pontine myelinolysis) may result in the locked-in syndrome (de-efferented state) [66,118,123].
This syndrome consists of the following signs:
1. Quadriplegia due to bilateral corticospinal tract involvement in the basis pontis
2. Aphonia due to involvement of the corticobulbar fibers innervating the lower cranial nerve nuclei
3. Occasional impairment of horizontal eye movements due to bilateral involvement of the fascicles of cranial nerve VI
Because the reticular formation is not injured, the patient is fully awake. The supranuclear ocular motor pathways lie dorsally and are therefore spared; therefore, vertical eye movements and blinking are intact (the patient may actually convey his wishes in Morse code). In thrombosis of the basilar artery, not infrequently a hemiparesis is present at an early stage (“herald hemiparesis” of basilar artery occlusion), when brainstem signs may be absent or few [49]. Therefore, a cerebral hemisphere localization is suggested, but in a few hours bilateral hemiplegia appears, associated with a locked-in syndrome or coma [49]. De-eerentation may also occur with purely peripheral lesions (e.g., polio, polyneuritis, myasthenia gravis).
DORSAL PONTINE SYNDROMES
Foville Syndrome.
This syndrome is due to lesions involving the dorsal pontine tegmentum in the caudal third of the pons. It consists of the following:
1. Contralateral hemiplegia (with facial sparing) which is due to interruption of the corticospinal tract.
2. Ipsilateral peripheral-type facial palsy which is due to involvement of the nucleus and fascicle (or both) of cranial nerve VII.
3. Inability to move the eyes conjugately to the ipsilateral side (gaze is “away from” the lesion) due to involvement of the PPRF or abducens nucleus, or both.
Raymond-Cestan Syndrome.
The Raymond-Cestan syndrome is seen with rostral lesions of the dorsal pons. It includes the following:
1. Cerebellar signs (ataxia) with a coarse “rubral” tremor which is due to the involvement of the cerebellum.
2. Contralateral hypesthesia with reduction of all sensory modalities (face and extremities) which is due to the involvement of the medial lemniscus and the spinothalamic tract.
3. With ventral extension, there may be contralateral hemiparesis (due to corticospinal tract involvement) or paralysis of conjugate gaze toward the side of the lesion (due to involvement of the PPRF).
PARAMEDIAN PONTINE SYNDROMES
Several clinical syndromes of paramedian pontine infarction have been described [11].
1. Unilateral mediobasal infarcts. These patients present with severe facio-brachio-crural hemiparesis, dysarthria, and homolateral or bilateral ataxia.
2. Unilateral mediolateral basal infarcts. Most patients show slight hemiparesis with ataxia and dysarthria, ataxic hemiparesis, or dysarthria clumsy hand syndrome.
3. Unilateral mediocentral or mediotegmental infarcts. Presentations include dysarthria—clumsy hand syndrome, ataxic hemiparesis with prominent sensory or eye movement disorders, and hemiparesis with contralateral facial or abducens palsy.
4. Bilateral centrobasal infarcts. These patients have pseudobulbar palsy and bilateral sensorimotor disturbances.
The most common etiology for paramedian pontine infarcts is small vessel disease; vertebrobasilar large vessel disease and cardiac embolism are less common causes [11].
An unusual nding observed in patients with unilateral paramedian pontine infarction consists of bilateral Wallerian degeneration of the middle cerebellar peduncles [156].
LATERAL PONTINE SYNDROMES
Marie-Foix Syndrome.
This syndrome is seen with lateral pontine lesions, especially those aecting the brachium pontis. It consists of the following:
1. Ipsilateral cerebellar ataxia due to involvement of cerebellar connections
2. Contralateral hemiparesis due to involvement of the corticospinal tract
3. Variable contralateral hemihypesthesia for pain and temperature due to involvement of the spinothalamic tract
Rostral lateral pontine infarcts can present with contralateral crural predominant hemiparesis or crural monoparesis. Lesions associated with crural hemiparesis primarily involve the lateral and dorsal pontine base, while lesions responsible for crural monoparesis primarily involve the dorsolateral pontine base [76].
As a rare occurrence, pontine lesions have been associated with anosognosia for the hemiplegia [43], blepharospasm [9], brief clonic jerking and other convulsive-like movements [133], jaw-opening dystonia, [40] hemidystonia [146], a focally enhanced startled response [163], symptomatic orthostatic tremor [13], dysarthria-dysmetria or dysarthria-facial paresis [136], body lateropulsion from paramedian tegmental involvement ventral to the fourth ventricle [164], truncal ataxia without limb ataxia [102], isolated bilateral ataxia due to
selective involvement of part of the decussation of the superior cerebellar peduncle [88], bilateral deafness [154], cheiro-pedal syndrome with numbness of hand and foot associated with hypesthesia and hypalgesia [74], painful Horner syndrome [31], contralateral hemihyperhidrosis [120], intraoral sensory loss [44], trigeminal neuralgia [119], ipsilateral transient eye and nose pain [41], isolated cranial nerve palsies [149], transient hemiageusia [86], disturbances of cognition and aect, pathologic crying, prodrome of inappropriate or
pathological laughter (fou rire prodromique) resulting from rostral and medial pontine involvement [61,136,147], rapid eye movement sleep behavior disorder occurring either in isolation or in association with narcolepsy [83,95]. In other circumstances, they have mimicked an acute peripheral vestibulopathy [150]. While lesions in the dorsolateral pontine tegmentum may cause vomiting, medial tegmental upper pontine lesions, probably aecting the PPRF bilaterally, may cause central reex hyperpnea, formerly called central neurogenic hyperventilation. Volitional central facial paresis results from lesions involving the contralateral corticobulbar bers. Emotional innervation of the muscles of facial expression is involuntary and of uncertain origin. Volitional type of facial paresis with unimpaired emotional movements to emotional stimuli has also been described indicating that the pathways subserving volitional and emotional input to the facial nucleus are still anatomically separated in the upper pons [153,158]. Conversely, emotional (mimetic) facial paresis has been noted with dorsolateral pontine lesions involving structures distinct from the corticobulbar fibers that mediate volitional facial innervation [72].
The Syndrome of Universal Dissociative Anesthesia
Universal dissociative anesthesia is a rare syndrome that has been described in a patient aected by combined right superior cerebellar artery occlusion, resulting in lateral superior pontine infarction, and left posterior inferior cerebellar artery occlusion, resulting in a left Wallenberg lateral medullary syndrome [159]. The patient had loss of pain and temperature sensation over the face, neck, trunk, and all extremities, whereas light touch, vibration, position, and deep pain sensation were preserved (dissociated sensory loss). This interesting lesson in localization was due to bilateral discrete interruption of spinothalamic fibers and the spinal nucleus and tract of the trigeminal nerve.
MESENCEPHALIC SYNDROMES
1. VENTRAL CRANIAL NERVE III FASCICULAR SYNDROME (WEBER’S SYNDROME)
A lesion affecting the cerebral peduncle, especially the medial peduncle, may damage pyramidal fibers and the fascicle of cranial nerve III.
This results in the Weber’s syndrome, which consists of the following:
1. Contralateral hemiplegia (including the lower face) due to corticospinal and corticobulbar tract involvement
2. Ipsilateral oculomotor paresis, including parasympathetic cranial nerve III paresis (i.e., dilated pupil)
This syndrome may be seen with intrinsic or extrinsic brainstem lesions and may even be the presenting sign of multiple sclerosis
When supranuclear fibers for horizontal gaze are interrupted in the medial peduncle, a supranuclear-type conjugate gaze palsy to the opposite side may occur (the midbrain syndrome of Foville).
2. DORSAL CRANIAL NERVE III FASCICULAR SYNDROMES (BENEDIKT’S SYNDROME)
A lesion affecting the mesencephalic tegmentum may affect the red nucleus, the brachium conjunctivum, and the fascicle of cranial nerve III . More ventral tegmental lesions result in Benedikt’s syndrome, which consists of the following
1. Ipsilateral oculomotor paresis, usually with a dilated pupil
2. Contralateral involuntary movements, including intention tremor, hemichorea, or hemiathetosis, due to destruction of the red nucleus
Similar clinical manifestations are noted with more dorsal midbrain tegmental lesions that injure the dorsal red nucleus and brachium conjunctivum (Claude’s syndrome) but with prominent cerebellar signs (e.g., asynergia, ataxia, dysmetria, dysdiadochokinesia) and no hemiballismus
The Nothnagel’s syndrome is a variant of the dorsal midbrain syndrome , and may not include a fascicular third nerve palsy
DORSAL MESENCEPHALIC SYNDROMES
Dorsal rostral mesencephalic lesions produce mainly neuro-ophthalmologic abnormalities. The dorsal mesencephalic syndrome (also known
as the Sylvian aqueduct syndrome, the Koeber-Salus-Elschnig syndrome, or Parinaud’s syndrome) [65] is most often seen with hydrocephalus
or tumors of the pineal region. This syndrome includes all or some of the following signs:
1. Paralysis of conjugate upward gaze (occasionally down-gaze)
2. Pupillary abnormalities (pupils are usually large with light-near dissociation)
3. Convergence-retraction nystagmus on upward gaze (especially elicited by inducing upward saccades by a down-moving optokinetic target)
4. Pathologic lid retraction (Collier’s sign)
5. Lid lag
6. During horizontal rexations, the abducting eye may move more slowly than the adducting eye (“pseudoabducens palsy”), perhaps
reflecting excess convergence tone
TOP OF THE BASILAR SYNDROME
Occlusive vascular disease of the rostral basilar artery, usually embolic, frequently results in the “top of the basilar” syndrome [24,97] due to
infarction of the midbrain, thalamus, and portions of the temporal and occipital lobes. An uncommon variant of this syndrome may also
result in bilateral paramedian midbrain ischemia [142]. This syndrome may also occur in patients with giant basilar artery tip aneurysms, in
patients with vasculitis, and after cerebral angiography [97]. This syndrome variably includes the following:
1. Disorders of eye movements. Unilateral or bilateral paralysis of upward or downward gaze, disordered convergence, pseudoabducens
palsy, convergence-retraction nystagmus, ocular abduction abnormalities, elevation and retraction of the upper eyelids (Collier’s sign), skew
deviation, and lightning-like eye oscillations.
2. Pupillary abnormalities. Small and reactive, large or midposition and fixed, corectopia, occasionally oval pupil.
3. Behavioral abnormalities. Somnolence, sleep-wake cycle abnormalities, peduncular hallucinosis, memory difficulties, agitated delirium.
4. Visual defects. Hemianopia, cortical blindness, Balint’s syndrome.
5. Motor and sensory deficits. Lesions causing pseudoabducens palsy with convergence-retraction nystagmus have been further mapped to the
midbrain-diencephalic junction [124]. In addition, isolated unilateral superior oblique palsies have been described in patients with
contralateral tegmental lesions of the trochlear nucleus and adjacent intraaxial trochlear nerve [152]. Likewise, isolated cranial nerve
palsies and cheiro-oral syndrome have been reported as the sole manifestation of small mesencephalic infarcts [2,149]. Furthermore,
strategically placed unilateral caudal paramedian midbrain lesions may produce bilateral cerebellar dysfunction [108].
Although the MR imaging characteristics of gliomas may be highly diagnostic in the pediatric population allowing for the potential use of PET imaging to attempt to determine the degree of malignancy, the heterogeneity of lesions in the adult population may not allow for the procurement of useful data until studies are conducted correlating preoperative PET imaging with histologic diagnosis
Although the MR imaging characteristics of gliomas may be highly diagnostic in the pediatric population allowing for the potential use of PET imaging to attempt to determine the degree of malignancy, the heterogeneity of lesions in the adult population may not allow for the procurement of useful data until studies are conducted correlating preoperative PET imaging with histologic diagnosis