[Primary neoplasm of unknown origin]

Cancers of unknown primary site constitute a heterogeneous group having in common their biological behaviour. We have analysed patients with cancer of unknown primary site admitted to University Hospital of Coimbra/Internal Medicine Service III from 1st January of 1992 to 30th June of 1998. The study included 26 patients corresponding to a prevalence of 2.5% malignant neoplasias; the median age of affected patients was 64 years old with a male-to-female ratio of 4.2:1. The most frequent histological type was well differentiated and moderately well differentiated adenocarcinoma, 46.1% of all cases. Three years global survival rate was 3.9%. The herein-reported prevalence is comparable to that found in recent literature, showing a good diagnostic skill. As expected, the prognosis was poor, revealing the disease's aggressiveness and the lack of efficient therapy in the majority of case.