Evaluation and management of the unknown primary carcinoma of the head and neck.

Squamous cell carcinoma of unknown primary origin in the head and neck is encountered as a recurring clinical problem in head and neck cancer clinics, affecting 3% to 25% of patients. This article describes the clinical presentation, appropriate evaluation, and treatment strategies for this important subgroup. Treatment--best carried out with multidisciplinary teams of specialists experienced in the care of head and neck cancer patients--is curative for most of these patients.