Carcinoma of Unknown Primary: Diagnostic Approaches for Radiologists

Carcinoma of unknown primary is an important and complex disease entity that presents challenges to interpreting radiologists. This article presents a comprehensive clinical, pathologic, and radiologic work-up and assessment for radiologists. It is important for the radiologist to know the p16, high-risk human papilloma virus, and Epstein-Barr virus status; nodal drainage patterns of head and neck squamous cell carcinoma; and the utility of various imaging modalities to help identify the primary site and guide therapy.Learning Objectives: To understand the clinical, pathologic, and radiologic evaluation of carcinoma of unknown primary (CUP); to provide an overview of the clinical and pathologic work-up for CUP that aids in imaging interpretation; and to recognize patterns of nodal involvement for identification of the primary disease