Transcript Nasopharyngeal carcinoma

Imaging of nasopharyngeal
carcinoma
ATTIA M, KOUKI S, LANDOULSI M,BOUGUERRA S,AROUSY,
BOUJEMAA H, BEN ABDALLAH N.
HEAD AND NECK : HN 21
INTRODUCTION

Nasopharyngeal carcinoma is a non-lymphomatous, squamous-cell
carcinoma that occurs in the epithelial lining of the nasopharynx.

This neoplasm shows varying degrees of differentiation and is frequently
seen at the pharyngeal recess (Rosenmüller’s fossa) posteromedial to the
medial crura of the eustachian tube opening in the nasopharynx.
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Many histological entities exist from Squamous Cell Carcinoma (SCC) to
the more frequent Undifferentiated Carcinoma of the Nasopharyngeal Type
(UCNT), and these entities share endemic areas throughout the world

the disease occurs with much greater frequency in southern China,
northern Africa, and Alaska.

While NPC may occur at any age, it has a bimodal distribution with the first
peak of occurrence in the 15–25 years age range and the second peak in
the fourth to fifth decade.

EBV infection is clearly associated with NPC.
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The symptomatology is variable and misleading.
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The diagnosis is based on endoscopy + biopsy.
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The imaging has an interest in:
-
The diagnosis (fossa of Rosenmüller + + +)
-
The staging of the tumor.
-
The post therapeutic surveillance.

The aims of our study are to :
-Remind the normal radioanatomy.
- Know the main routes of extension.
- State the purpose of imaging during the post treatment
monitoring .
Normal anatomy

The nasopharynx is a mucosal lined,
tubular-shaped midline structure
which constitutes the superior
extendt of the airway.

Its cranial border is limited by the
skull base(sphenoid sinus and clivus)
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The posterior margin of the
nasopharynx extends to the
prevertebral muscles and soft
tissues.
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Anteriorly, the nasopharynx freely
communicates with the nasal cavity
through the posterior choane.

Laterally it abuts the pyramidalshaped parapharyngeal spaces.
Normal anatomy

The rigid and tough pharyngobasilar
fascia provides structural support for
the nasopharynx.

The fascia forms a three-sided curtain
which opens anteriorly toward the
nasal cavity.

Superiorly, the fascia is fixed to the
skull base from the pterygoid plates to
the carotid canal.

Lateraly it is adherent to the
cartilaginous portion of the eustachian
tube.
It forms a closed and resistant barrier
The sinus of Morgagni is the only
defect through which the eustachian
tube and the levator veli palatini
muscle pass.
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

As a result of the close proximity of the foramen lacerum and foramen
ovale to the sinus of Morgagni and eustachian tube there exists a potential
pathway for the spread of disease to cranial cavity.
the foramen ovale
the foramen lacerum
Radioanatomy
Radioanatomy
nasopharynx
Rosenmuller’s
fossa
T2 weighted image
T1 weighted image
Radioanatomy
nasopharynx
T2 weighted image
CT image
Extension pathways.

The nasopharyngeal tumor may extend straight up to the base
of the skull, down to the oropharynx and to the nasal cavities
forward.
Extension pathways

Lateral to the pharyngobasilar
fascia, the nasopharynx is bounded
by four spaces which are divided
by three layers of deep cervical
fascia.

These include the masticator
(infratemporal fossa), the
parapharyngeal, the carotid and
the parotid spaces.

Lateral deviation and or
infiltration of the parapharyngeal
fat are sensitive indicators of the
spread of nasopharyngeal disease.
Dark : pharyngobasilar fascia.
Blue : parapharyngeal space.
Green : the masticator space.
Red : the carotid space.
Imaging techniques
Computed tomography


Performing exam
Extending from the skull base
to the thoracic inlet
( cervical adenopathy)
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Thin slices ( 1-3mm)

intravenous contrast
enhancement ( 2cc/Kg)
Advantages:
Detecting bone erosion and
cervical lymph node.
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Limits:
Analysing the peripharyngeal
spaces and perinervous
extension.
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MRI
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Technique
Exploration in the three plans
of the space in T1, T2 and
T1 gadolinium + / - FatSat.
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Advantages:
- Extension to the skull base.
Extension to the deep face
spaces .
- Perinervous and perivascular
extension.
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limits:
Claustrophobia.
Metallic components
TNM classification
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T1: Tumor confined to the nasopharynx.
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T2: Extension to:
• T2a: nasal cavity and / or oropharynx,
• T2b: parapharyngeal space.
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T3: Extension bone and / or sinuses.
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T4: intracranial extension, cranial nerves, the hypopharynx, with
infratemporal fossa and / or the orbit.
TNM classification
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N0: No regional metastatic ADP.
• N1: metastatic (s) unilateral (s) ADP (s), <or equal to 6 cm, above
the supraclavicular fossa.
(NB:ADP located in the midline are considered
ipsilateral).
• N2: metastatic bilateral ADP<or equal to 6 cm in the largest
dimension, above the supraclavicular fossa.
• N3: metastatic (s) ADP (s):
• N3A:> 6 cm,
• N3b: at the supraclavicular fossa.
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M:
• M0: no metastases,
• M1: metastases.
Distant metastases: + + + bones, liver, lung, pleura
Results
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5 patients were evaluated with MRI before and after contrast material.
10 patients with advanced stages had CT tomgrpahy with intravenous
contrast enhancement.
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MRI is most efficient for local staging especially in stage 1 and 2 (TNM
classification) which correspond to 5 patients in our study.
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Computed tomography is performing to determinate bone extension and
metastatic locations (liver, lung…) in 10 patients with advanced stage tumors.

T1 tumor
Blunning of left fossa of Rosenmuller and
enlargement of levator palatini muscle
T2a tumor
nasopharyngeal tumor with oropharyngeal extension
T2b tumor
nasopharyngeal tumor with parapharyngeal extension
throuugh pharyngobasilar fascia
T4 tumor
nasopharyngeal tumor with infratemporal fossa extension
T4 tumor
Coronal computed tomography showing bony involvement of
the sphenoid sinus and intracranial extension
DISCUSSION
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Computed tomography and MRI have respective specific advantages and
disadvantages.
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MR seems to provide a more accurate evaluation of the extent of the
primary tumor; in fact, MR is able to identify as retropharyngeal nodes
findings previously misdiagnosed on CT as oropharyngeal or
parapharyngeal invasion.
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Moreover, it provides new pieces of information such as the infiltration of
long muscles of the neck and pterygoid muscles that, in most cases, cannot
be clearly imaged with CT; according to some authors, MR can also detect
cavernous sinus and early perineural invasion.
DISCUSSION
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The advantages of CT over MR in imaging bone details, especially when the
bone contains little or no fat marrow, are well known.
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This suggests that CT should continue to be part of the pretherapeutic
workup whenever the base of skull involvement is suspected or possible,
but not clearly detected with MR. In fact, upstaging leads to a substantial
change of treatment volume and may hint that a locally aggressive
treatment should be delivered.

As far as follow-up is concerned, the basic clinical question of differentiating
between postradiation changes and recurring tumor seems to be less often
uncertain with MR than with CT.
Therefore, MR, even if not a panacea, may be the preferred modality.
However, the cases with subtle bone erosions or cortical defects on staging
CT are probably best followed up with this modality.
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DISCUSSION
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FOLOW UP
MRI + +: once a year during 5 years and then every 5 years
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Goals:
- evaluate tumor response to treatment
- Tracking early recurrence (T4: 60%
recurrence at 10 years)
-Guiding biopsies
Conclusion
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The imaging constitutes a key element in the diagnostic
and therapeutic care of the nasopharyngeal carcinoma.
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It aims at determining exactly the point of departure and
the extension of the tumor in order to establish the
classification: tumor-nodes-metastases and to specify the
fields of the irradiation.
References

Staging and follow-up of nasopharyngeal carcinoma: magnetic resonance
imaging versus computerized tomography.
Patrizia Olmi and al. Int. J. Radiation Oncology Biol. Phys.,Vol. 32, No. 3, pp.
795-800, 1995.

Bilan d’extension d’une tumeur du nasopharynx. F Dubrulle. Journées
françaises de radiologie 2006.

Cancer du nasopharynx. F Cohen, O Monnet, F Casalonga, A Jacquier,V
Vidal, JM Bartoli et G Moulin. J Radiol 2008;89:956-67.

Current understanding and management of nasopharyngeal carcinoma.
Tomokazu Yoshizaki and al. Auris Nasus Larynx 39 (2012) 137–144