Carcinoma of unknown primary

The management of metastases of unknown primary origin presents considerable challenges to the treating physician, because therapy decisions are often determined by the nature of the primary tumor. Metastases originating from an unknown source are known as “CUP tumors” (carcinoma of unknown primary). Incidence of CUP tumors ranges from 0.5 to 10% of all newly diagnosed tumors [2, 8, 11, 15, 19, 26]; they are more prevalent in males and the mean age of diagnosis is about 60 years. Frequent first sittings for the metastatic lesions are lymph nodes (37%); of these, 31% are located in the head and neck region, which is the most common site for metastases of unknown origin [14].