A 30-year-old Chinese man presents with cervical lymphadenopathy, bloody nasal discharge, and conductive hearing loss. Nasopharyngoscopy reveals a submucosal mass in the fossa of Rosenmüller. EBV IgA-VCA serology is elevated. Biopsy shows undifferentiated carcinoma with prominent lymphocyte infiltrate. Per WHO 2022 classification, this tumour type is:

• A WHO Type III — Undifferentiated carcinoma (lymphoepithelioma, EBV-associated) ✓
• B WHO Type I — Keratinizing squamous cell carcinoma
• C WHO Type II — Non-keratinizing carcinoma (differentiated subtype)
• D Basaloid squamous cell carcinoma with lymphoid stroma

Explanation

WHO classification of nasopharyngeal carcinoma: Type I (keratinizing SCC) is not consistently EBV-associated and is common in non-endemic areas; Type II (non-keratinizing, differentiated) and Type III (non-keratinizing, undifferentiated — the 'lymphoepithelioma') are strongly EBV-associated and endemic in South China and Southeast Asia. Type III has a prominent reactive lymphocytic infiltrate (hence lymphoepithelioma), shows elevated EBV IgA-VCA titers, is highly radiosensitive, and carries a better prognosis than Type I when treated with concurrent cisplatin + IMRT. The fossa of Rosenmüller (pharyngeal recess) is the most common site of origin.

Reference: Dhingra Diseases of Ear, Nose and Throat, 7th ed.

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Written and medically reviewed by the StethoPrep medical team.