Carcinoma with unknown primary tumor (CUP syndrome).

Approximately 10% of adenocarcinomas are first seen without a detectable primary tumor. The clinical state that results when a metastatic deposit is more symptomatic than its primary I have termed the CUP (carcinoma unknown primary) syndrome. By definition CUP tumors are incurable by current treatment but their management often includes extensive and expensive efforts to detect the organ of origin. This article stresses the pitfalls in clinical diagnosis and management and outlines an empiric, palliative approach to therapy.