Computed tomography of nasopharyngeal carcinoma. A review of CT appearances in 56 patients.

Axial CT findings of 56 patients with biopsy-proven nasopharyngeal carcinoma (NPC) were reviewed retrospectively to evaluate the region of origin of the tumor and the sites of spread of the disease. In all patients asymmetry of the mucosal airway contour with blunting of the fossa of Rosenmüller was seen, usually associated with infiltration of the levator palatini muscle. The earliest lesion of NPC arose in this region, and in 64% of cases the tumor had infiltrated into the adjacent parapharyngeal space with loss of its normal fat density. Superior intracranial extension was the most common site of deep infiltration from here (45% of patients) with opacification of the sphenoid sinus in 41% and bony destruction of the skull base in 29%. Invasion into the retropharyngeal space (38%) and carotid space (23%) were the next most common sites of infiltration. Invasion into the prevertebral space was seen in 14%. Anterior spread to the masticator space including the infratemporal fossa was an uncommon finding (14%). T-staging of these patients by CT was also done using both the AJC and Ho classification systems. Lymph node metastases were found in many patients (38%), most commonly in the retropharyngeal nodes, internal jugular nodes including jugular-digastricus nodes and the spinal accessory nodes, respectively. CT remains the most reliable technique for staging and assessing the extent of NPC, both prior to and after radiotherapy, and should be used not only for T-staging of the disease, but also for N-staging. It is recommended that axial scans should be routinely extended down the neck to the clavicles in all patients with NPC.