Carcinoid tumor of the kidney presenting as a large abdominal mass: report of a case.

Carcinoid tumors are known to occur frequently in the gastrointestinal tract and they can develop in nearly every organ system. However, a carcinoid tumor of the kidney is an extremely rare entity and only 38 cases have been reported in the English literature. We herein describe the 39th case of primary renal carcinoid tumor, found in a young Japanese woman 2 months after delivery. The pathologic similarities of our case with those of previously reported cases are briefly reviewed together with some aspects of clinical features and prognostic factors of this rare disease.