Contrast CT (axial plane)
A 63-year-old woman presents to the emergency department with left serous otitis media for one-month duration, associated with xerophthalmia and inability to close her left eye. There was no relevant medical or traumatic history.
CT was performed and showed a large enhancing mass in the nasopharynx, partially obliterating it, extending to the torus tubarius and tubal recess, thus causing middle ear obstruction.
On magnetic resonance imaging (MRI), the lesion appeared as a hypointense mass on T1-weighted images, with intermediate signal-intensity on T2-weighted images and marked enhancement upon contrast administration. The mass extended superiorly and invaded the foramen ovale, anteriorly and laterally without a cleavage plane with the pterygoid muscles. It also extended postero-externally abutting the deep left parotid lobe and postero-medially involving the retropharyngeal, pre-vertebral and carotid spaces, encasing the internal jugular as well as invading the internal carotid artery. Close proximity with cranial nerves (CN) IX, X, XI and XII was also noted as well as extensive bilateral lymph node involvement. The left mastoid was infiltrated by a satellite lesion with a similar imaging profile, strongly suggestive of a metastatic deposit.
Nasopharyngeal carcinomas (NC) are the most common primary neoplasm of the nasopharynx (70% of cases) [1-4]. They are rare in the Western population but one of the most common malignancies in Asia [1-6].
There is a male predominance (3:1) and peak incidence is between the 5th and 7th decades [1-6]. Causes include both genetic susceptibility and environmental factors, and there is a strong association with Epstein-Barr virus [1-6].
NCs originate from squamous cells and are divided into three histological subtypes, according to the World Health Organization [1-2,4-6]. The keratinisng subtype is most frequent in non-endemic areas, is associated with cigarette smoking and alcohol and has the worst prognosis [2,4]. Non-keratinising and non-differentiated subtypes share a similar behaviour, both having radiotherapy sensitivity and a better prognosis [2,4,6].
At presentation, patients usually have cervical nodal or distant metastases (75–90% and 5–41% of cases, respectively) [2-4]. It is not uncommon for patients to present with symptoms from adjacent cranial nerve involvement, orbital or skull base invasion and extension to adjacent spaces, such as pain, nasal discharge and hearing loss.
The majority of NCs arise in the posterolateral recess of the pharyngeal wall (fossa of Rosenmuller)  and given that the nasopharynx is a central structure, its evaluation is difficult by physical examination alone . In this regard, imaging and, particularly, MRI, plays an important role in diagnosis, staging and follow up of this disease [1-3].
On CT, NC appears as an infiltrative mass with moderate contrast enhancement . MRI is the method of choice for NC evaluation, showing a hypointense mass on T1-weighted images, with moderately hypointense or intermediate signal intensity (higher than the muscle) on T2-weighted images and moderate to marked enhancement (higher than the normal mucosa), after contrast administration [1,2].
The mainstay of treatment is radiation therapy [1-5]. Most relapses will occur within the first three years and thus, a baseline follow-up study should be made 3 to 6 months after treatment . While some authors recommend a follow-up scan on a yearly basis for three years and then clinical follow-up, others suggest follow-up based only on clinical factors [2,3]. It is worth mentioning the role of PET-CT not only for detection of distance metastasis, but also for monitoring patients after therapy .
It is important for radiologists to be aware of the imaging presentation of nasopharyngeal carcinomas and perform a detailed evaluation of the nasopharynx in the context of a middle ear effusion. Nowadays, MRI is the study of choice for detection of local extension, including CN and perineural extension, pre-operative evaluation and recurrence.
Written informed patient consent for publication has been obtained.
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