6. Parapharyngeal Space
• The parapharyngeal space is
located deep within the neck
lateral to the pharynx and
medial to the ramus of the
mandible.
• Shape of an inverted pyramid
with the floor at the skull
base and it’s tip at the
greater cornu of the hyoid
bone
• Two compartments :
– Prestyloid
– Retrostyloid
7. Lymphatic Drainage
•
•
•
•
•
Richest lymphatic plexus in the head and neck
region.
Submucosal lymphatics congregate at the
pretubal region – “pretubal plexus”.
These then pass on to the retropharyngeal
nodes as 8 -12 trunks which decussate in the
midline.
Lymphatic trunks pierce the level of the base of
the skull and run between the pharyngobasilar
fascia and the longus capitis.
The lymphatic trunks drain in three directions:
– To the retropharyngeal nodes.
– To the posterior triangle nodes and the
confluence at the 11th, cranial nerve and the
jugular lymph node chains, situated at the tip of
the mastoid.
– To the Jugulo-digastric nodes
8. RPLN
• The retropharyngeal nodes are present
in two groups.
– Median group.
– Lateral group.
• The median group consists of 1 - 2
nodes interconnected in the midline.
• The lateral group consists of 1- 3 nodes
located between the lateral aspect of
the posterior pharyngeal wall and the
carotid artery.
• These nodes are present from the
vertebral levels C1- C3.
• The superior-most lymph node of the
latter group is also known as the node
of Rouviere.
• This node lies in front of the arch of the
Atlas being separated from it by the
longus colli muscle.
13. Genetic path
Normal Epithelium
Deletion of Chromosomes 3p and 9p
Low Grade Dysplasia
Inactivation of Chromosome p14, 15 and 16
High Grade Dysplasia
EBV infection
Gain Chromosome 12
Deletion 11 and 13
Invasive Carcinoma
P53 Mutation
Metastatic Carcinoma
14. Local Invasion
Nasal cavity & PNS
Base of Skull, Clivus
Orbital invasion
Lateral Parapharyngeal space
Middle ear cavity
Oropharynx (tonsillar pillars)
C1 vertebrae
ANT
17. Hematogenous Spread
• 3% @diagnosis, 18-50% during the course.
• Mets in Advanced neck node states (N3). If in
lower neck, chances are higher.
• Bone > Liver> Lungs (A study by Hui et al.)
18. Clinical Features
•
•
•
•
Most common: Asymptomatic cervical lymphadenopathy (87%)
MC node involved is the upper posterior deep cervical (direct drainage
from the lateral pharyngeal),parapharyngeal,and jugulodigastric nodes.
The midjugular and midposterior cervical nodes are the next most
commonly involved, followed by the lower jugular and supraclavicular
nodes
Other presenting symptoms:
– Epistaxis (73%),Nasal twang to speech
– Unilateral serous otitis media ( 62%)
– Cranial nerve palsy(20%): Multiple inv; 2 syndromes
– Sore throat : Oropharyngeal extension
– Pain: Compression of Vth cranial nerve ( facial pain)
– Trismus: Mandibular nerve involvement or pterygoid muscle invasion
– Dermatomyositis (1%)
20. CN Syndromes in NPC
The Petrosphenoidal syndrome of Jacod:
• unilateral neuralgia of the trigeminal (V)
• unilateral ptosis (III),
• complete ophthalmoplegia (III, IV, and V)
• amaurosis (II).
21. Syndrome of Retroparotid Space of Villaret:
• difficulty in swallowing (IX and X);
• perversion of taste in the posterior third of
the tongue (IX);
• Sensory issues in mucous membrane of the
soft palate, pharynx, and larynx; respiratory
and salivary problems (X);
• hemiparesis of the soft palate; paralysis and
atrophy of the trapezius and
sternocleidomastoid muscles (XI)
• unilateral paralysis and atrophy of the tongue
(XII)+/-Horner syndrome(Cerv symp chain)
22. •
•
•
•
Work up:
History and Clinical examination incl. Ear
FOE
Basic Investigations: CBC,CXR,LFT
Staging:
–
–
–
–
–
MRI of Nasopharynx or CT
USG Abdomen
CT thorax /upper abdomen
PET scan
Bone Scans(for N3 status)
• Other Investigations
– EBV Serology-Ig A ,Anti VCA titres,EBV DNA levels
24. Staging
• Several staging systems are in use:
– Complex anatomy and spread patterns
– Lack of international consensus:
• Separate Chinese, Hong Kong and American staging systems
• Systems available:
–
–
–
–
–
Fletcher (1967)
Ho’s staging (1978)
IUAC (1988)
Huaqing staging (1994)
AJCC(2010)
25. Comparison
System
Staging
T1
Fletcher
(1967)
Ho (1978)
IUAC
(1988)
Huaqing
(1994)
T2
T3
T4
< 1 cm
diameter
> 1 cm but confined to
nasopharynx
Beyond nasopharynx
Involving skull base or
cranial nerves
Confined to
nasopharynx
Extending to nasal fossa or
oropharynx
Bone/ Cranial nerve/
orbital /
hypopharyngeal /
infratemporal fossa
involvement
NA
Limited to one
site in
nasopharynx
Extending to two sites in
nasopharynx
No bony destruction
Bony destruction
including eustachian
tube
Limited to
nasopharynx
Involving the nasal cavity,
oropharynx, anterior
cervical vertebrae, PPS
before SO line
Pterygoid process /
posterior cranial nerve
/ posterior cervical
vertebrae / BOS /
PPS beyond SO line
Infratemporal fossa /
cavernous sinus / PNS
/ direct invasion of C2
or C1 / anterior cranial
nerves
26. Ho’s vs AJCC 2010
HO
AJCC
T1
Tumor confined to the nasopharynx
Tumor confined to the nasopharynx, or
e/t oropharynx and/or nasal cavity
without parapharyngeal extension
T2
Tumor extended to the nasal fossa,
oropharynx, or adjacent muscles or
nerves below the base of the skull
Tumor with parapharyngeal extension
T3
Tumor extending beyond T2 limits:
T3a:Bone involvement below the base
of the skull.
T3b:Involvement of the base of the
skull
T3c:Involvement of the CN(s)
T3d:Involvement of the orbits,
laryngopharynx (hypopharynx), or
infratemporal fossa
-
Tumor involves bony structures of skull
base and/or paranasal sinuses
T4
Tumor with intracranial extension and/or
involvement of cranial nerves,
hypopharynx, orbit, or with extension to
the infratemporal fossa/masticator space
27. A study:Staging of nasopharyngeal carcinoma: Evaluation of N-staging by Ho
and UICC/AJCC systems
A.W.M. Lee, W. Foo, Y.F. Poon, C.K. Law, D.K.K. Chan, S.K.O, S.Y. Tung,
J.H.C. Ho
Ho's system was superior in predicting distant failures, while the UICC/AJCC system
was superior for nodal failures.
N-staging can be further optimized by a newly proposed system incorporating fixity
(movable versus fixed), level (upper-mid versus lower), size (greatest diameter ⩽6
cm versus >6 cm), and laterality (unilateral versus bilateral) as staging criteria.
28. AJCC system: T staging
• T1: Tumor confined to the nasopharynx ,oropharynx or nasal cavity
• T2: Tumor with parapharyngeal extension
• T3: Tumor involves bony structures of skull base and/or
paranasal
sinuses
• T4: Tumor with intracranial extension and/or involvement of cranial
nerves, hypopharynx, orbit, or with extension to the infratemporal
fossa/masticator space
30. N staging
• NX: Status cannot be assessed
• N0: No regional lymph node metastasis
• N1:
– Unilateral metastasis in lymph
node(s), < 6 cm in greatest
dimension, above the supraclavicular
fossa
• N2:
– Bilateral metastasis in lymph node(s),
< 6 cm in greatest dimension, above
the supraclavicular fossa
• N3:
– N3a: Metastasis in a lymph node(s)
>6 cm
– N3b: Extension to the supraclavicular
fossa
Ho’s Triangle
32. STAGING GROUP
Stage III includes patients with T 1 –T2
disease with bilateral neck nodes or patients
with T3 disease unilateral or bilateral neck
nodes.
Stage IVA includes patients with T4 disease
while IVB includes patients with N3 disease
Stage IVC stands for distant mets.
33. Pathology
• Some authors consider carcinomas to be of two types:
– Keratinizing
– Non keratinizing
• Others consider carcinomas to be of 4 types:
–
–
–
–
Keratinizing Squamous
Non Keratinizing Squamous
Lymphoepithelioma
Undifferentiated carcinomas
• WHO 3 types:
– Type I : SCC 20% -- elderly, less EBV titres, best prognosis
– Type II : Non Keratinizing carcinoma 30-40%
– Type III : Undifferentiated carcinoma 40-50%
34. Endemic NPC
•
•
•
•
•
•
•
•
•
Known to occur in China, Hong Kong, South Eastern Asia, Greenland
Associated with EBV virus infection
In India similar pathology seen in Kashmiris.
Present a decade younger.
Not associated with smoking or alcohol consumption
WHO II and III
Associated with more advanced disease at presentation
Nodal stage also more advanced and more frequently involved.
Both chemo and radio sensitive
– Histologically more vascularized (Better Rx response)
– Greater % of cell in the growth fraction.
•
•
Better loco regional control and survival than sporadic variants.
Several markers for predicting biological behavior
35. Prognostic factors
•
•
•
•
Most important Nodal status F/b T stage
Parapharyngeal extension is associated with a poorer prognosis.
A Chinese series found that 4th cranial nerve involvement – poor
prognosis.
Nodal disease status:
– Bilateral cervical lymphadenopathy
– Supraclavicular lymphadenopathy
– Lymph node fixity
•
Lymphoepithelioma histology & undifferntiated histology: better local
control for T2 and T3
(Perez CA, Devineni VR, Marcial-Vega V, et al)
• Molecular markers:
– Ki -67 over expression
– P 53
– E – cadherin expression
The posterior wall of the nasopharynx is made up of four anatomic layers: the mucous membrane of the pharynx; the pharyngeal aponeurosis; the superior constrictor muscle of the pharynx; and the buccopharyngeal fascia, which is loosely connected with the adjacent prevertebral fascia. The muscular wall of the nasopharynx is incomplete. In the upper nasopharynx, the lateral walls consist of only two layers: the mucous membrane and the pharyngeal aponeurosis. This area of muscular deficiency is called the sinus of Morgagni, through which the cartilaginous part of the eustachian tube enters the pharyngeal wall along with the levator veli palatini muscle.
Superiorly bound by the base of the skull and overlies the carotid canal, jugular foramen, and hypoglossal foramen. The inferior border is the junction of the posterior belly of the digastric muscle and the greater cornu of the hyoid bone. Medially, the boundary is made up of the buccopharyngeal or visceral fascia overlying the superior pharyngeal constrictors. The lateral boundary is made up of the fascia over the medial pterygoid muscle, the ramus of the mandible, the posterior belly of the digastric muscle, and the fascia over the retromandibular deep portion of the parotid gland. Anteriorly the limit is the pterygomandibular raphe. The posterior limit is the dorsal layer of fascia making up the carotid sheath.
Fascia which extends from the styloid process to the tensor veli palantini muscle, called the tensor-vascular-styloid fascia, because it also contains the ascending palatine artery and vein, divides the parapharyngeal space into an anterolateral or prestyloid, and a posteromedial, or retrostyloid compartments.
The prestyloid compartment contains fat, a portion of the retromandibular parotid gland, and some lymph nodes.
The retrostyloid compartment contains the internal carotid artery, internal jugular vein, cranial nerves IX-XII, sympathetic chain, and lymph nodes.
The parapharyngeal nodes superiorly are connected to the node of Rouviere in the lateral most retropharyngeal space.
3 PATHWAYS:1) lateral pharyngeal wall to the lateral pharyngeal (parapharyngeal) nodes in the lateral pharyngeal or retroparotid space. The uppermost of this group of nodes is the lateral retropharyngeal node of Rouvier
2)From these lateral pharyngeal nodes, efferent channels pass to the jugular chain, especially to the jugulodigastric (subdigastric) nodes. Some lymphatic channels may bypass the lateral pharyngeal wall and drain directly to the jugulodigastric node
3) Another path is by direct channel to the deep nodes of the posterior triangle, the spinal accessory nodes. The uppermost node of this chain lies beneath the sternocleidomastoid muscle at the tip of the mastoid process.
The incidence is highest among people from southern China, particularly those originating from Kwantung Province, followed by the Chinese mixed populations of Southeast Asia and indigenous populations in Alaska.[1],[2] It is of intermediate incidence in North Africa and in the Philippines and it is rare among whites and Japanese. The age-adjusted incidence rate (per 100,000 population per year) ranges from 28.8 in Hong Kong, 17.2 in indigenous populations in Alaska, 16.8 in Singapore, 4.6 in the Philippines, 2.8 in Algeria, and 0.6 in the United States and Japan.[3],[4] The peak incidence occurs in the fourth and fifth decade of life, and the male/female ratio is 2 : 1 to 3 : 1.
Inactivation of the tumor suppressor genes namely the Chromosomes 14, 15 and 16 are considered central steps in the pathogenesis of high grade dysplasia.
The cause of NPC is most likely multifactorial. (1) viral, (2) genetic, and (3) environmental. Various environmental factors such as poor ventilation, occupational exposures to smoke or dusts, and diet have been implicated. The ingestion of salted fish during early childhood has been suggested as the most important environmental factor among the southern Chinese with NPC.[2,9,10] Dimethylnitrosamine, a carcinogen found in salted fish, has been shown to induce carcinoma in the upper respiratory tract of rats.[9]
Lymph nodes are involved at presentation in 89%. There is unilateral involvement in 39% and bilateral involvement in 51%. Low-grade squamous cell carcinomas produce fewer metastases (73%) than high-grade carcinomas (92%). Metastases to submental and occipital nodes may appear when there is blockage of the common lymphatic pathways either by massive neck disease or by an untimely neck dissection.
Upper posterior cervical, parapharyngeal, and jugulodigastric nodes. The midjugular and midposterior cervical nodes are the next most commonly involved, followed by the lower jugular and supraclavicular nodes
The exact incidence of cranial nerve involvement varies from series to series being higher in Asian series and those using CT scans. 12% patients have clinically detected cranial nerve palsy while 29% have radiologically detected cranial nerve involvement.
A, Sagittal T1-weighted MRI scan demonstrates abnormal soft tissue (arrows) in the region of the left cavernous sinus extending from the upper nasopharynx. B, Axial postcontrast T1-weighted image following fat saturation demonstrating an invasive carcinoma that extends across midline to involve both Rosenm?ller's fossae (arrows). C, Coronal T1-weighted postcontrast MRI scan demonstrating the invasive carcinoma of the nasopharynx (black arrows) with extension through the foramen ovale along the course of the third division of the fifth cranial nerve into the cavernous sinus (white arrows). D, Axial postcontrast T1-weighted image through the cavernous sinus demonstrating an enhancing tumor that has expanded the left cavernous sinus (arrows) as it courses along the third division of the fifth cranial nerve.
SO line is the line connecting the styloid process to the posterior edge of the foramen magnum.
Ho’s System was a better predictor of prognosis than the 1988 AJCC system but it failed to include the prognostic importance of parapharyngeal extension. Further 5 stages were given which was not same as the western standard. The new AJCC system includes the nodal staging of the Ho’s system which is of prognostic significance
Midline nodes are considered unilateral.
Supraclavicular zone or fossa is relevant to the staging of nasopharyngeal carcinoma and is the triangular region originally described by Ho. It is defined by 3 points: (1) the superior margin of the sternal end of the clavicle, (2) the superior margin of the lateral end of the clavicle, and (3) the point where the neck meets the shoulder. Note that this would include caudal portions of Levels IV and V. All cases with lymph nodes (whole or part) in the fossa are considered N3b.
The Lymphoepitheliomas subtype consists of undifferentiated cells forming syncitial mass is along with which large number of small lymphocytes are interspersed. Some authors believe that this histology confers a higher local control rate, as well as better prognosis than squamous cell carcinoma. Overall, it has been found that patients with undifferentiated histology have a higher proportion of advanced stage at presentation.
The biological markers include IgA , IgE , anti-VCA often are predictors of relapse. Similiarly high ADCC levels are correlated with a better prognsis.