A Unique Case of Primary EBV-Positive, HPV-Negative Nasopharyngeal Carcinoma Located in the Tonsil.

Nasopharyngeal carcinomas (NPC) are non-keratinizing squamous cell carcinomas of the nasopharynx associated with Epstein-Barr virus (EBV). When occurring outside of the nasopharynx, they are referred to as lymphoepithelioma-like carcinomas (LELCs) and present the same morphology as NPC. LELC have been described in other head and neck regions such as the salivary glands and the soft palate. LELC can also occur in the oropharynx, are associated with human papillomavirus (HPV) and are typically negative for EBV. We herein present a unique case of a 78-year-old Chinese male with EBV-positive, HPV-negative NPC of the left tonsil. His presenting symptom was a left-sided lymph node. There was no evidence of nasopharyngeal lesion seen on physical examination, PET and MRI. The patient was treated with curative-intent external beam radiotherapy which delivered 70 Gy (Gy) to the gross tumour and lymph nodes, and 56 Gy electively to the ipsilateral neck using a volumetric modulated arc therapy technique. This is the first case of primary tonsil EBV-positive NPC described in the literature.