A 50-year-old presents with a painless firm neck mass at level II for 6 weeks. FNAC shows squamous cell carcinoma. Panendoscopy and CT of neck/chest/abdomen are negative for a primary lesion. HPV p16 immunostaining of the FNAC is strongly positive. The most appropriate next step is:
- A PET-CT scan followed by EUA and directed biopsies ✓
- B Bilateral tonsillectomy and ipsilateral tongue base mucosectomy to find the occult primary
- C Radical neck dissection followed by radiotherapy to all mucosal sites
- D Ipsilateral tonsillectomy only
Correct answer: A. PET-CT scan followed by EUA and directed biopsies
Explanation
For unknown primary HPV-positive SCC at level II, PET-CT has the highest sensitivity (~45%) to detect the primary tumor before invasive procedures. If PET-CT is negative, EUA with directed biopsies of the ipsilateral palatine tonsil, tongue base, and nasopharynx (the commonest occult primary sites in HPV+ disease) is performed. Bilateral tonsillectomy is considered after negative directed biopsies; it is not the first step.
Reference: Dhingra Diseases of Ear, Nose and Throat, 7th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.