Nasopharyngeal carcinoma pathophysiology

On microscopic histopathological analysis, abundant dense eosinophilic cytoplasm and prominent lymphoid component are characteristic findings of nasopharyngeal carcinoma.

Genes involved in the pathogenesis of nasopharyngeal carcinoma include:

• MDM2
• TP53
• RAD51L1
• TNFRSF19
• CDKN2A
• CDKN2B

• Nasal cavity involvement – common in early disease^[1]

The tumor arises from epithelial cells on the surface of the nasopharynx.

Features:^[2]

• Prominent lymphoid component (Lymphoepithelioma) – key feature
• Features of squamous cell carcinoma:
  • Cohesive cells with:
    • Abundant dense eosinophilic cytoplasm
    • Central nuclei +/- small/indistinct nucleoli

Nasopharyngeal carcinoma may be classified according to microscopic features into 3 subtypes:^[3]

• Well-differentiated (keratinizing type)
• Moderately-differentiated (nonkeratinizing type)
• Undifferentiated (most strongly associated with Epstein-Barr virus infection)

• 
  Undifferentiated nasopharyngeal carcinoma – low power
• 
  Undifferentiated nasopharyngeal carcinoma – med. power
• 
  Undifferentiated nasopharyngeal carcinoma – high power

Immunohistochemistry stains for nasopharyngeal carcinoma include:

• EBER positive
• p16 negative^[4]

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