The nasopharynx has a cuboidal shape. The lateral walls are formed by the
eustachian tube and the fossa of Rosenmuller. The roof, sloping downward from
anterior to posterior, is bordered by the pharyngeal hypophysis, pharyngeal
tonsil, and pharyngeal bursa with the base of the skull above. Anteriorly, the
nasopharynx abuts the posterior choanae and nasal cavity, and the posterior
boundary is formed by the muscles of the posterior pharyngeal wall.
Inferiorly, the nasopharynx ends at an imaginary horizontal line formed by the
upper surface of the soft palate and the posterior pharyngeal wall.
Unlike other squamous cell cancers of the head and neck, nasopharyngeal cancer
does not appear to be linked to excess use of tobacco and alcohol. Factors
thought to predispose to this tumor include Chinese (or Asian) ancestry,
Epstein-Barr virus (EBV) exposure, and as yet unknown factors that result in
very rare familial clusters.
Symptoms and signs at presentation include painless, enlarged lymph nodes in
the neck (present in approximately 75% of patients and often bilateral and
posterior), nasal obstruction, epistaxis, diminished hearing, tinnitus,
recurrent otitis media, cranial nerve dysfunction (usually II–VI or IX–XII),
sore throat, and headache. In the patient who presents with only cervical
adenopathy, the finding of EBV genomic material in the tissue after
amplification of DNA with the polymerase chain reaction lends strong evidence
for a nasopharyngeal primary tumor, and a concerted search should be conducted
in that area.
Tumors of many histologies can occur in the nasopharynx but this discussion,
like the American Joint Committee on Cancer nasopharynx staging, refers
exclusively to those of squamous cell type.
Diagnosis is made by biopsy of the nasopharyngeal mass. Workup includes
careful visual examination (by mirror or endoscopic examination); documentation
of the size and location of the tumor and neck nodes; evaluation of cranial
nerve function and hearing; skull films (especially base of skull views),
evaluating neural foramina; complete computed tomographic (CT) scan or magnetic
resonance imaging (MRI) with views delineating the upper and lower extent of
the lesion; chest x-ray; hemogram; and chemistry panel. Any clinical or
laboratory suggestion of distant metastasis may prompt further evaluation of
other sites. Careful dental and oral hygiene evaluation and therapy is
particularly important prior to initiation of radiation treatment. MRI is
often more helpful than CT scans in detecting abnormalities and in defining
Major prognostic factors adversely influencing outcome of treatment include
large size of the tumor, higher T stage, and the presence of involved neck
nodes. Other factors linked to diminished survival that were present in some, but not all,
studies include age, nonlymphoepithelial histology, long interval between
biopsy and initiation of radiation therapy, diminished immune function at
diagnosis, incomplete excision of involved neck nodes, pregnancy during
treatment, locoregional relapse, and certain EBV antibody titer patterns.