The nasopharynx is a small, tubular structure above the soft palate that connects the nose to the oropharynx. Cancers that arise from this area are usually squamous cell carcinomas that behave differently than the other head and neck cancers. Most common place of origin is the fossa of Rosenmuller, which is the pharyngeal recess. Virus-related oncogenesis is a common theme in head/neck cancers. Oropharyngeal cancers are associated with human papillomavirus (HPV) infection, and nasopharyngeal cancers (NPC) are associated with Ebstein-Barr virus (EBV). The exact pathogenesis is still unknown. However viral oncogenes LMP-1, LMP-2, and EBNA1 have been known to play an important role. In areas with a high incidence of disease, most cases are related to EBV infection. Although HPV related nasopharyngeal cancers have also been reported, no clear association has been established.
The clinical behavior of nasopharyngeal cancers varies depending on its histological subtype. The World Health Organization (WHO) has classified nasopharyngeal carcinoma into the three subtypes based on histology. Type 1 is keratinizing squamous cell carcinoma which is associated with EBV infection in around 70% to 80% of the cases. Type 2 is differentiated non-keratinizing carcinoma, and type 3 is undifferentiated nonkeratinizing carcinoma and is the most common form of nasopharyngeal cancer. The latter 2 types are also most responsive to treatment. Almost all cases of type 2 and type 3 are related to EBV and occur in the area where EBV is endemic. Nasopharyngeal cancer with basaloid features is a newer, rarer histologic category, known to behave aggressively. Treatment does not vary based on histologic subtypes. In general, mortality related to nasopharyngeal cancers has improved in the last decade owing to early detection and advances in treatment.