Renal Medullary Carcinoma.

Renal medullary carcinoma, also referred to as the seventh sickle cell nephropathy, typically affects young African Americans with sickle cell trait, or, less frequently, patients with sickle cell disease. The existence of renal medullary carcinoma without a concomitant hemoglobinopathy is a topic of controversy. The typical patient is a young male of African or Mediterranean descent, with hematuria and/or flank pain. Most patients have metastatic disease at the time of presentation. The tumor is characteristically a poorly circumscribed mass in the medullary region, commonly showing variable amounts of hemorrhage and necrosis. Microscopically, a characteristic reticular or cribriform pattern with a striking desmoplastic stromal response and a robust mixed inflammatory infiltrate is observed. Collecting duct carcinoma, malignant rhabdoid tumor, urothelial carcinoma, and other subtypes of renal cell carcinoma are in the differential diagnosis. Because of the advanced stage of disease at presentation and the aggressive nature of this malignant neoplasm, survival is poor even with chemotherapy; however, isolated reports of prolonged survival have been documented.