Recurrent carcinosarcoma of the renal pelvis. Case report.

Carcinosarcoma is a malignancy that occurs very rarely in the renal pelvis; thus, only a very limited number of cases has been documented. These tumors are composed of both carcinomatous and sarcomatous elements. We report here a case of a carcinosarcoma composed of well-differentiated, keratinizing, squamous carcinoma cells and high-grade sarcoma cells. Differently from the cases described so far, this carcinosarcoma of the renal pelvis was characterized by the quick recurrence, following complete surgical resection, as a highly disseminated high-grade sarcoma.