Medulloblastoma- A primitive neuroectodermal tumors (PNETs) is the most common malignant brain tumor of childhood (WHO IV)
arising from the vermis in the inferior medullary velum.
It comprises up to 18% of all pediatric brain tumors.
WNT and Shh pathway plays major role in its pathogenesis.
c-erbB-2 (HER2/neu) oncogene expression has prognostic value. Norcantharidin, Vismodegib, Sonidegib are the future in medulloblastoma.
Dr Vandana, cranio spinal irradiation, radiotherapy, medulloblastoma, cancer, radiation, treatment, diagnosis, management, natural history of medulloblastoma, signs & symptoms of medulloblastoma,
current approach, future advancements
Dr Vandana, cranio spinal irradiation, radiotherapy, medulloblastoma, cancer, radiation, treatment, diagnosis, management, natural history of medulloblastoma, signs & symptoms of medulloblastoma,
current approach, future advancements
Craniopharyngioma is thought to arise from ectodermally derived epithelial remnants of rathke’s pouch and there craniopharyngeal duct.
Neoplastic transformation of cells derived from tooth primordia give rise to adamantinomatous craniopharnygioma, whereas
such transformation in cells derived from buccal mucosa primodia give rise to papillary type
This presentation reviews the current neurosurgical management of patients with medulloblastoma, including the data on molecular subtyping; uses “medulloblastoma” as a springboard to discuss other topics / tumor cell biology in general; and formulates research questions to further advance neurosurgical basic science.
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
Brain metastasis is an advance diseases with poor overall prognosis management of which is full of controversies. This slide aims to make metastasis simplified.
Craniopharyngioma is thought to arise from ectodermally derived epithelial remnants of rathke’s pouch and there craniopharyngeal duct.
Neoplastic transformation of cells derived from tooth primordia give rise to adamantinomatous craniopharnygioma, whereas
such transformation in cells derived from buccal mucosa primodia give rise to papillary type
This presentation reviews the current neurosurgical management of patients with medulloblastoma, including the data on molecular subtyping; uses “medulloblastoma” as a springboard to discuss other topics / tumor cell biology in general; and formulates research questions to further advance neurosurgical basic science.
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
Brain metastasis is an advance diseases with poor overall prognosis management of which is full of controversies. This slide aims to make metastasis simplified.
Brain tumours are responsible for approximately
2% of all cancer deaths. Central nervous system
tumours comprise the most common group of
solid tumours in young patients, accounting for
20% of all paediatric neoplasms. The overall incidence
of brain tumours is 8–10 per 100 000 population
per year. A study by the United States
Department of Health in 1966 showed the incidence
to be 21 per 100 000 per year at 2 years old
and 1 per 100 000 during the teenage years. The
incidence increases after the 4th decade of life to
reach a maximum of 16 per 100 000 per year in the
7th decade. There has been an intense debate concerning
the increased incidence of brain tumours,
especially in the elderly, but this possible increase
could be explained due to the advent of CT and
MRI leading to better detection of tumours.
Classification
The general brain tumour classification is related
to the cell of origin, and is shown in Table 6.1.
Table 6.2 shows the approximate distribution
of the more common brain tumours.
This chapter will discuss the tumours derived
from the neuroectoderm and metastatic tumours.
The following chapters will describe the benign
brain tumours and pituitary tumours.
Aetiology
Epidemiology studies have not indicated any
particular factor (viral, chemical or traumatic)
that causes brain tumours in humans, although a
range of cerebral tumours can be induced in animals
experimentally. There is no genetic predis
Water dynamic of UBE Unilateral Biportal Endoscopy.pptxsuresh Bishokarma
Unilateral Biportal Endoscopy (UBE) is a fluid medium surgery. Continuous saline output is critical
Hydrostatic pressure. Managing the fluid is the key to successful surgery. It use the principle of Bernauli’s and Pascal law. Explore the water dynamic of UBE surgery.
Posterior lumbar fusion vs Lumbar interbody fusion Evidence based.pptxsuresh Bishokarma
Lumbar degenerative disc diseases (LDDD): irreversible process in lumbar disk architecture.
Sparse literature to choose proper technique to address these pathology with or without fusion surgery.
A clear benefit of lumbar fusion surgery: lowered pain and disability scores.
Lumbar surgery rates have increased steadily over time, and hence related complications.
Evidence of the superiority of one technique over the other is sparse.
Surgery offers greater improvement compared with non-operative treatment in LDDD.
Surgery in disc herniation resulted in faster recovery, However no added benefit of fusion surgery.
There was no obvious disadvantage of posterolateral fusion without internal fixation in patient with spondylosis.
Among patients with lumbar spinal stenosis without spondylolisthesis, decompression plus fusion surgery may not result in better clinical outcomes.
In patient with spondylolisthesis with or without stenosis, fusion is more effective than laminectomy in achieving a satisfactory outcome. Decompression only had the least satisfactory outcome.
Patients who underwent interbody fusion may have significantly higher fusion rates compared to posterior lumbar fusion only.
TLIF has advantages over PLIF in the complication rate, blood loss, and operation duration. The clinical outcome is similar, with a slightly lower postoperative ODI score for TLIF.
In the end, The choice of technique is still greatly based on the surgeons’ preference and experience.
Brain abscess may have hematogenous spread: Pneumococcus common or via Contiguous spread. Risk factors includes pulmonary abscess or AV fistulas, congenital cyanotic heart disease, immunocompromised, chronic sinusitis/otitis, dental procedures. Intraventricular rupture of abscess is life threatening. Timely diagnosis and treatment is the goal.
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.
Pineal gland is essentially an extra axial midline structure lying at the roof of dienchephalon rostral to the quadrigeminal cistern surrounded by important neurovascular structure, occurring in the geometric center of brain with same depth of trajectory had made the surgery in this region a formidable challenge to neurosurgeons, however radical resection must be the goal in selected pathologies, if not pure germ cell tumor.
Before embarking on an approach, the surgeon should be familiar with both the ventricular anatomy and the options for optimally Accessing lesions in third ventricle is a surgical challenge because of its difficult corridor as well as deeper location, need of neural incision, preservation of vascular, thalamus and hypothalamus and likely risk of fornix injury.
Brain arteriovenous malformations (bAVM) are abnormal connections of arteries and veins in the brain, forming a tangled web of vessels instead of a normal capillary network treated with multimodalities including, SRS, embolisation and Microneurosurgery.
This slides updates the management of AVM highlighting the importance of SM grading, Pollock radiation grading etc.
Brain abscess is a common neurosurgical emergencies, of which periventricular warrants urgent attention either medically or surgically. This algorithmic approach may help understand the very essentials of Brain abscess.
Angulation, trajectory and depth of screw placement in spine is not everyone's cup of tea unless you have a very clear idea of its ergonomics and dynamics.
Radiosurgery is a discipline that utilizes externally generated ionizing radiation in certain cases to inactivate or eradicate a defined target(s) in the head or spine without the need to make an incision. Its uses in Neurosurgery is immense.
Gliomas are the commonest tumor of brain arising from the supportive cells of the brain with diverse form and presentation the treatment of which is surgical and demands adjuvant therapy for most of circumstances.
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.
Dandy–Walker malformation (DWM) encompasses cystic dilatation of the fourth ventricle, complete or partial agenesis of cerebella vermis and enlarged posterior fossa while Dandy–Walker variant (DWV) comprises cystic posterior mass with variable hypoplasia of the cerebella vermis and no enlargement of the posterior fossa.
The caroticocavernous fistula is a specific type of dural arteriovenousfistula characterized by abnormal arteriovenous shunting within the cavernous sinus.
A caroticocavernous fistula results in high-pressure arterial blood entering the low-pressure venous cavernous sinus.
This interferes with normal venous drainage patterns and compromises blood flow within the cavernous sinus and the orbit.
Vascular crowding in the ventricle of brain is the chorioid plexus, the primary function of which is to secrete CSF has immensely diverse function which is still the huge scope in neuroscience exploration.
Liliequist membrane may be understood as a projection formed by an arachnoid membrane extending from the dorsum sellae to the mammillary bodies coined after Liliequist (1956). It has surgical importance in Endoscopic third ventriculostomy and cisternostomy.
The most common cause of death in young is non other than Head injury. The modern advances not only gave human mankind a luxury but with high velocity injury there is high burden of head injury too. This slide is updated with BTF 2016 guideline
Explore natural remedies for syphilis treatment in Singapore. Discover alternative therapies, herbal remedies, and lifestyle changes that may complement conventional treatments. Learn about holistic approaches to managing syphilis symptoms and supporting overall health.
Couples presenting to the infertility clinic- Do they really have infertility...Sujoy Dasgupta
Dr Sujoy Dasgupta presented the study on "Couples presenting to the infertility clinic- Do they really have infertility? – The unexplored stories of non-consummation" in the 13th Congress of the Asia Pacific Initiative on Reproduction (ASPIRE 2024) at Manila on 24 May, 2024.
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 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
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
Pulmonary Thromboembolism - etilogy, types, medical- Surgical and nursing man...VarunMahajani
Disruption of blood supply to lung alveoli due to blockage of one or more pulmonary blood vessels is called as Pulmonary thromboembolism. In this presentation we will discuss its causes, types and its management in depth.
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.
1. cka
Dr. Suresh Bishokama, MS
MCH Neurosurgery resident
Department of Neurosurgery, Upendra Devkota Memorial National Institute of
Neurological and Allied Sciences
Bansbari, Kathmandu
MEDULLOBLASTOMA
2. Cushing Report: 1930
Coined Medulloblastoma: Bailey and Cushing
1983: PNET
HISTORY
3. Medulloblastoma is the most common malignant brain tumor of childhood (WHO IV) and
comprises up to 18-30% of all pediatric brain tumors.
Medulloblastomas are typically midline cerebellar lesions arising from the vermis in the
inferior medullary velum; however, in older children and adults they can arise from the
cerebellar hemispheres.
Medulloblastomas are related to primitive neuroectodermal tumors (PNETs) and occur
exclusively in the posterior fossa.
INTRODUCTION
4. Overall medulloblastomas account for 12-25 % of all pediatric CNS tumors, and 30-40%
of pediatric posterior fossa tumors.
They are also seen in adults but only account for 0.4-1.0% of adult brain tumor.
M:F ratio of 2:1, although this is only true of group 3 and 4 tumors
They usually present in childhood with 77% of cases before the age of 19.
The median age of diagnosis is 9 years.
When diagnosed in adulthood, they typically present in the 3rd and 4th decades and are
more likely to arise in atypical locations (see below).
When they present in adulthood, there is often a better prognosis. (Younger the poorer)
EPIDEMIOLOGY
5. N Nitroso compound
Vegetables are protective
JC virus
Genetic conditions: Li-Fraumani, Gorlin, Turcot
P53, IGF, c-MYC and N-MYC oncogenic transcription factor, Apoptotic pathway: Bcl-2
ASSOCIATION
6. Medulloblastoma to arise from the external granule layer of the developing cerebellum
and others have proposed that the cell of origin arises from a subventricular progenitor
zone.
PATHOGENESIS
7. WNT is a ligand for the transmembrane protein FRIZZLED and major cytoplasmic
component of the WNT pathway is APC/GSK-3B/AXIN complex.
In absence of WNT this complex phosphorylates B catenin, thereby targeting it for
degradation. B catenin in nucleus promotes cellular proliferation.
WNT PATHWAY
8. Sonig Hedge Hog (SHH)
Sonig Hedge Hog (SHH) is a diffusible mitogenic protein that binds to the
transmembrane receptor protein (PATCHED 1-PTCH1).
In the absence of SHH, PTCH1 binds with SMO.
This complex inhibit glioma associated oncogene homolog (GLI) and hence cellular
proliferation.
However, when PTCH1 binds with SHH, inhibitor effect of SMO-PTCH1 complex are
reversed leading to activation of GLI and enhanced oncogenesis.
9. WNT tumours should be identified by two of the following markers:
Nuclear ß-catenin accumulation (IHC)
Monosomy 6 (whole chromosome loss) by FISH
CTNNB1 mutation
WNT pattern by DNA methylation or by gene expression profiling
SHH, Group 3 and Group 4
IHC
c-myc amplification (FISH)
Genome-wide methylation
10. Classic : (90%): Undifferentiated cells with hyperchromatic nuclei, (Homer
wright rosette suggesting neuronal differentiation, Blue tumor
Desmoplastic : (6%): Classic + Glomeruli (pale island of collagen): Least
aggressive
Nodularity MBEN : Diffuse variant in <3 years child: good prognosis
Large cell Anaplastic : (4%): early seed, high mitosis: poor prognosis
HISTOLOGICAL SUBTYPES
Homer-Wright rosettes composed of neoplastic cells concentrically arranged around fibrillary processes
11. Diffuse masses of small, undifferentiated oval or round cells.
Some medulloblastomas show neuronal, glial and other differentiation.
Nuclear moulding due to compactness inside cell.
Neuronal differentiation is manifested by neuropil and rosette formation.
Rosettes are groups of tumor cells arranged in a circle around a fibrillary center.
Mature neurons may also be found infrequently. Glial differentiation in some tumors is reflected by
GFAP-positive cells. There may also be differentiation along oligodendroglial or ependymal lines.
CLASSIC MEDULLOBLASTOMA
12. Pale nodules are composed uniform round to spindle shaped neuronal-appearing
cells which are not as active mitotically as the surrounding darker tumor.
They are present within a reticulin-poor fine fibrillary background
DESMOPLASTIC MB
13. Large cell anaplastic medulloblastoma composed of sheets of highly atypical cells.
A focus of necrosis is present just above the center of the image.
The tumor cells have irregular hyperchromatic nuclei with nuclear molding and little cytoplasm
ANAPLASTIC MB
14. Medulloblastoma can spread along cerebrospinal fluid (CSF) pathways and also rarely to
systemic sites (bone, lung).
Leptomeningeal dissemination constitutes the most common pattern of recurrence for
Group 3 and Group 4 patients, and usually leads to a quick progressive clinical decline
despite therapy.
15. New type: Medulloblastoma NOS.
CLINICOPATHOLOGICAL AND MOLECULAR
CHARACTERISTICS OF MB SUBGROUPS
CLINICOPATHOLOGICALAND MOLECULAR CHARACTERISTICS OF MB SUBGROUP
CHARACTER WNT 10% SHH: 25% GP3: 25% GP4: 40%; MC
GENDER M=F M=F M>F M>F
PEAK AGE Children Children Infants Children
OCCURRENCE
Arise from foramen of
luschka (CP angle)
Laterally cerebellar
hemisphere, and vermis
4th ventricle 4th ventricle
ENHANCEMENT
Intensely enhancing like
ependymoma but diffusion
restriction
Intermediate Intermediate Usually non-enhancing
HISTOLOGY Classic, rarely LCA
Desmoplastic/MBEN,
Classic, LCA
Classic, LCA Classic, LCA
GENE MUTATED
CTNNB1, TP53 CTNNB1, TP53,
3q gain, 9p deletion
MYC amp, OTX2,
SMARCA4
KDM6A, MYCN
SNCAIP
duplication
IHC
B-catenin +(including
nuclear and
cytoplasmic)
CTNNB1 mutation,
GAB1 (-)
Cytoplasmic B-Catenin+;
GLI amplification; SMO
mutation;
MYCN+
GAB1+, YAB1+, PTCH1+,
SMO+, P53±
MYCN+++;
YAB/GAB-
Minimal
amplification;
CDK6+;
YAB/GAB (-)
METASTASIS Low Extremely low High Frequent
PROGNOSIS
Best prognosis Intermediate Poor Intermediate
16. Molecular group /
Immunoreactivity
GAB1 ß-catenin YAP1
WNT Negative Nuclear +
Cytoplasmic +
Nuclear +
Cytoplasmic
SHH Cytoplasmic Cytoplasmic + Nuclear +
Cytoplasmic
Non-SHH/WNT Negative Cytoplasmic - Negative
MOLECULAR SUBGROUPS AND
IMMUNOREACTIVITY
One of the techniques that can be implemented widely across the globe is IHC-
based sub classification
17. IMMUNOREACTIVITY/
MOLECULAR GROUP
WNT SHH Non-SHH/WNT
ß-catenin (Nuclear) + - -
GAB-1 - + -
YAP1 + + -
p53 ±
Molecular subgroups and immunoreactivity
Surrogate IHC
Additional for Group 3: c-myc amp (FISH)
Additional for WNT: Monosomy Chr 6
(FISH)
18. Homer-Wright rosettes composed of neoplastic cells concentrically arranged around
fibrillary processes are a common histological feature.
Isochromosome17q was confirmed as the most common genetic alteration in
medulloblastomas, found in 28% of specimens.
Synaptophysin, Neuron enolase, neurofilament protein, tubulin
Metastases may have different immunohistology different from the actual primary.
PATHOLOGY
19. Short time before diagnosis (<3months)
Morning headache, vomiting, lethargic
Features of raised ICP including papilloedema and diplopia (CN VI)
Truncal and appendicular ataxia, nystagmus, bulbar and facial palsy (brainstem),
Head tilt (tonsil descent in FM)
Macrocrania (infant),
Drop mets (Back pain, urinary retention and leg weakness): ~10-35% of MB seeds at the
time of dx and Extraneural mets occurs in 5% (sometime promoted by shunt: 10-20%;
overestimated ???)
CLINICAL PRESENTATION
20. Classic features of a medulloblastoma on computed tomographic (CT) scan are
increased density on the non-contrast scan, midline location, well-defined margins, and
dense, homogeneous enhancement with injection of contrast, surrounding vasogenic
edema.
Calcification (22%) and cyst formation (59%)
The hyperdensity on plain CT scan, seen in medulloblastoma and in some ependymomas,
is secondary to the high cellularity of these tumors that have scanty cytoplasm and areas
of desmoplasia.
WORK UP
21. MRI: There is a high degree of variability of MR appearances of medulloblastoma.
T1 sequences are usually iso-hypointense to white matter and hyperintense on T2
sequences.
Tumor enhancement can be both homogeneous or heterogeneous.
Similar to ependymoma, approximately14% of medulloblastomas may show foraminal
extension.
Banana sign (4th vent drapes around medulloblastoma unlike ependymoma where tumor
encroach 4th vent)
HCP: 85-90%
MRI BRAIN WITH CONTRAST
26. FEATURES MEDULLOBLASTOMA EPENDYMOMAS PILOCYTIC ASTRO HEMANGIOBLASTOMA
Origin Roof of 4th V Floor Cerebellar Cerebellar
Clinical features
Age
Acute
5-15
Chronic
3-8
Chronic
5-15
Chronic
40-60
VHL: Young
NE-CT Hyperdense (cellularity) Hypo Hypo Hypo
Heterogenicity Less More Solid cystic Solid cystic
T1W-MRI Hypo Hypo Hypo Hyper (also cyst)
T2W-MRI Iso to Hyper Hyper Hyper Hyper, flow void
Mural Nodule None None May be present May be present
Enhancement Most (E); Non (gr 4) to
intense (WNT)
Intense Solid enhances Intense
Perilesional edema - - - +
Calcification Less More None Less
Hemorrhage Less More Rare Less
Extension into
cisternal spaces
Less More Nil Less
Diffusion restriction Yes No No No
MEDULLOBLASTOMA VS EPENDYMOMA
27. MR spectroscopy may also be distinctive
SHH
little or no taurine
low creatine
Group 3 or 4
Taurine peak
high creatine
MRS
28. MRI SPINE to assess the severity of diseases (Mets)
Leptomeningeal seeding on MRI is found in approximately 33% of patients.
The spinal canal is the most common location of seeding; however, the supratentorial
compartment may also be involved.
Nodular or diffuse enhancement along the leptomeninges, nerve roots in the spinal canal,
or cranial nerves in the CPA are common findings of CSF seeding.
MRI SPINE
29. MRI and CSF cytometry may miss 14% of seeding
CSF cytometry
32. 1. Establish histological diagnosis
2. Maximally resect tumor mass
3. Relieve hydrocephalus
AIMS OF SURGERY
33. MEDULLOBLASTOMA
SURGICAL RESECTION
HCP TREATED
>3 YRS <3 YEARS
STANDARD RISK POOR RISK CHEMOTHERAPY
FOLLOW UP OR DELAY XRT OR
LOCAL FIELD XRT
PROTON
CSI OR REDUCED DOSE CSI+
CHEMO
CSI+ ADJ CHEMO (CCNU,
CISPLATIN, VINCRISTINE OR
CHEMO ON RESEARCH
PROTOCOL
FOLLOW
RISK STRATIFICATION
1. Age (less than <3 or >3 years); Presence of disseminated disease (M1-4); Extent of surgical
resection (<1.5 or >1.5cm residual) and Histological differentiation
(5 years PFS among group: 77% vs 35-50%)
Better outcome: Girls; WNT:good/ LCA/non SHH/WNT: Poor
MEDULLOBLASTOMA
FIG: PROPOSED ALGORITHM FOR TREATMENT OF PATIENT WITH MEDULLOBLATOMA
XRT: OPTIMAL DOSE
35-40Gy to whole CSI +
10-15 Gy boost to tumor
bed (PF) and to any spinal
mets, all fractionated over
6-7 weeks
Reduce dose by 20-25% or Chemo
Chemotherapy improves 5-yr PFS survival (87% vs 33%)
Low dose XRT 25 Gy
34. Currently risk stratification is based on age (less than 3 years of age), presence of
disseminated disease (M1-4, and extent of surgical resection (<1.5 or >1.5cm residual)
and histological differentiation along glial, ependymal or neuronal line. (5 yrs PFS
among group: 77% vs 53%)
In cases in which there is greater than 1.5 cm of residual tumor, a repeat procedure
should be considered, if safe and anatomically feasible, to place the patient in the best
prognostic category.
Medulloblastoma is a radiosensitive tumor and incorporation of radiotherapy has become
a standard of care in treatment of children older than 3 years of age.
RISK STRATIFICATION
PROGNOSTIC FACTORS
Low-risk patients.
Nuclear accumulation of CTNNB1*
CTNNB1* mutations
Monosomy stratifies
*WNT subgroup markers
High-risk patients:
MYC/MYCN amplication and
isochromosome 17q
35. It is generally agreed now that most patients do not require pre-operative shunting.
However, 20-35% may need post-operative shunt.
Shunt risk of peritoneal dissemination: 10-20%.
Pre-operative shunt: Demerit: Tumoral hemorrhage, seeding, upward herniation.
If the drain continues to drain at the height of 20cm, hydrocephalus is shown to progress
or pseudomeningocele develops.
SHUNT OR NOT
36. TREATMENT STRATEGY
MECHANISM OF ACTION OF CHEMOTHERAPY
DRUG MOA SIDE EFFECT
CISPLATIN Induces cellular apoptosis by cross-linking DNA Ototoxicity and nephrotoxicity, dys-electrolytemia
CYCLOPHOSPHAMIDE Alkylating agent Hemorrhagic cystitis, infertility
LOMUSTINE Alkylating agent Myelosuppression, myeloid leukemia
VINCRISTINE Microtubule inhibitor that prevents cell division by
binding to the tubulin component of microtubules and
leading to metaphase arrest
Peripheral neuropathy. Muscle weakness, SEVERE
CONSTIPATION
37. Radiation therapy (XRT) should begin ~30 days following definitive surgery.
Historically, the entirety of the cerebellum was radiated.
Therapy is delivered in daily fractions of 1.8 Gy to a final dose of 54 Gy - 59.4 Gy.
Craniospinal irradiation (CSI) is delivered to the entire brain and spine and given
concurrently with primary site radiation for the first 13 days of therapy, to a total dose of
23.4 Gy (1.8x 13days)
RADIOTHERAPY
Posterior fossa ®: 1.8 Gy for 1 months (54-59.4 Gy)
CSI ®: 1.8 Gy for 13 days (23.4 Gy)
MEDULLOBLASTOMA
38. The current standard of care for average risk medulloblastoma among >3 yrs child is
gross total resection, postoperative craniospinal radiation of 23.4 Gy with a tumor bed
irradiation t of 54 Gy, followed by 12 months of chemotherapy.
Cyclophosphamide, vincristine, cisplatin and peripheral stem cell rescue. (5 years EFS
~70%)
Child <3 years: chemotherapy has been used to delay radiation therapy until nervous
system matures or reduced (20-25% of total) dose of XRT.
Administration of focal radiation to tumor bed is insufficient to control medulloblastoma,
even if there is no evidence of disseminated disease at diagnosis.
Consequently, irradiation of entire neuraxis is critical in the treatment of
medulloblastoma.
CURRENT STANDARD OF CARE
39. Cognitive decline, endocrine insufficiency, hearing loss, growth retardation, vascular
complications, leukoencephalopathy and secondary malignancies.
SIDE EFFECTS OF RADIATION
40. Proton therapy: Bragg peak: capacity to deliver targeted radiation while sparing normal
structure. Target avoiding spinal growth plate, auditory canal, pituitary fossa.
NOVEL IRRADIATION PROMISE
41. MRI within 48 hours to minimize detection of non-tumoral post-operative changes
Postoperative surveillance imaging of the brain and spine in patients with medulloblastoma
is routinely employed at many institutions with 3–6 month intervals during the first 5 years
following initial diagnosis in the hope of detecting recurrent disease earlier.
.
POST OP IMAGING
42. Post op neurological morbidity: 25-57%
Cerebral mutism (25%); Dysarthria persist after mutism recover.
Recurrence: Collin’s law to define period of recurrence (age at diagnosis + 9 months;
Autologous stem cell rescue to deliver chemotherapy at dose that may provide better
response was tried limited by hematologic toxicity.
OUTCOME
43. 5 years survival:
M0: 70%
M1: 57%
M ≥2: 40%
Prognosis is most strongly influenced by molecular subtype
WNT: very good
SHH: infants good, others intermediate
group 3: poor
group 4: intermediate
Outcome is good among girls
Recurrence occurs in duration of 4-20 months.
Survival after recurrence: 5months (poor)
PROGNOSIS
44. Expression of the c-erbB-2 (HER2/neu) oncogene is useful in the staging of
medulloblastomas.
Increased c-erbB-2 expression reflects an increase in the proliferative activity of
a tumor (widely used in breast cancer staging).
No CSF metastases, complete surgical resection and negative c-erbB-2
expression: 5-year-survival 100%.
No CSF metastases, complete surgical resection and positive c-erbB-2
expression: 5-year-survival 54%.
CSF metastases and/or incomplete surgical resection: 5-year-survival 20%.
c-erbB-2 (HER2/neu) oncogene expression
45. Protein phosphatase inhibitor Norcantharidin for WNT: + nuclear B- catenin.
Smoothened (SMO) inhibitors: Vismodegib and Sonidegib targets Shh pathway
Suppress MYC-related pathway activity.
FUTURE
46. GOOD
1. WNT
2. B Catenin
3. Classic, Desmoplastic
CONFOUNDERS OF OUTCOME
BAD
1. GAB1, YAB1
2. TP53
3. Large/Anaplastic
4. MYC amplification
47. Thank you
NATIONAL INSTITUTE OF NEUROLOGICAL AND ALLIED SCIENCES, BANSBARI, KATHMANDU
MEDULLOBLASTOMA
UPENDRA DEVKOTA MEMORIAL NATIONAL INSTITUTE OF NEUROLOGICALAND ALLIED SCIENCES,
BANSBARI, KATHMANDU