Tumor Spread from Nasopharyngeal Visceral Space

Epidemiology

The most common lesion in the parapharyngeal space at the level of the nasopharynx is direct tumor extension from a nasopharyngeal carcinoma. Nasopharyngeal carcinomas spread along well-defined routes, with parapharyngeal extension being the most frequent direction of spread. This finding may be seen in > 40% of patients.

Pathology

Histologically, 98% of nasopharyngeal carcinomas are of the undifferentiated variety. They often have heavy lymphocytic infiltration, which explains why they were previously called lymphoepitheliomas. The tumor is intimately related to the Epstein-Barr virus because almost all patients have significantly raised antibody titer against the virus. Nasopharyngeal carcinomas show aggressive local spread, skull base erosion, and intracranial extension. There is nodal metastasis in 80% of patients at presentation.

Clinical Findings

There are no specific signs and symptoms that suggest invasion of the parapharyngeal space. The involvement of the parapharyngeal space is a radiological diagnosis made usually during tumor staging.