Occult squamous cell carcinoma of the uvula detected by F-18 FDG PET/CT in a case of carcinoma of unknown primary in the head and neck.

Incidence of unknown primary head/neck tumors with metastatic cervical lymphadenopathy at time of diagnosis is approximately 2% to 9%. Detecting site of original disease is challenging. We present a 75-year-old woman with bulky unilateral level 2 and 3 lymphadenopathy. Clinical examination and computed tomography (CT) did not reveal detectable abnormalities except neck-node metastases; biopsy indicated metastatic squamous cell carcinoma (SCC). F-18 FDG PET/CT imaging was performed to detect the primary tumor site, which revealed a small metabolically-avid lesion in uvula, biopsy demonstrated SCC, the origin of metastatic disease. F-18 FDG PET/CT imaging of unknown primary head/neck tumors can have positive impact in identifying small occult primary tumor foci.