Nasopharyngeal carcinoma

Causesl and predisposing factors

·    Hereditary (common in Africa and southern China)

·    EBV infection (genome identified in tumour epithelial cells of undifferentiated and non-keratinizing subtypes)

·    Age (common in children in Africa and adults in southern China)

Histologic classification and histologic features of each subtype

·    Keratinizing squamous cell carcinomas

-    Composed of polygonal cells with dense, eosinophilic cytoplasm

-    Squamous pearls may be seen

-    Intercellular bridges are seen between tumour cells

-    Cell nuclei are round to oval with sharp, well-defined edges, hyperchromasia, inconspicuous nuclei

·    Non-keratinizing squamous cell carcinomas

-    Composed of polygonal cells with lack of obvious keratinization

o    Focal squamous pearls may be present; intercellular bridges are seen between tumour cells

-    Cell nuclei are round to oval with inconspicuous nucleoli

·    Undifferentiated carcinomas (with an abundant non-neoplastic lymphocytic infiltrate)

-    Large epithelial cells with oval or round nuclei, prominent nucleoli with indistinct cell borders in a syncytium-like array

-    Admixed with the epithelial cells are abundant, normal, mature-appearing lymphocytes

-    Two patterns may be seen:

Regaud’s pattern: cells are arranged in compact nests

Schminke’s pattern: cells assume diffuse syncytial growth

Patterns of spread

·    Tend to grow silently in nasopharynx, tonsils, upper airway, or posterior tongue

·    Can extend to soft tissue, oropharynx, parapharyngeal space, bony structures and paranasal sinuses, intracranially with involvement of cranial nerves, to hypopharynx, infratemporal space, orbit or masticator space

·    Often spread to cervical nodes or distant sites

Treatment and prognosis

·    Radiotherapy is treatment of choice (undifferentiated variant is most radiosensitive; keratinizing variant is the least radiosensitive)

·    Single and combined chemotherapy is used as an adjunct in locally advanced disease

·    Prognosis is 50-70% 3-year survival