[Bellini duct carcinoma treated with partial nephrectomy: a case report].

We report a rare case of collecting duct carcinoma of the kidney (Bellini's duct carcinoma). A 37-year-old woman visited our hospital with a chief complaint of asymptomatic hematuria. We suspected right renal pelvic tumor from the detection of round filling defects in the upper calyces of the right kidney by image diagnoses. A ureteroscopic biopsy revealed a low grade renal cell carcinoma. Therefore, she received right partial nephrectomy immediately. Histological examination of the surgical specimen showed a highly differentiated adenocarcinoma with papillary proliferation besides the collecting duct epithelium. With the results of the strongly positive patterns of immunohistochemical staining with high molecular cytokeratin and peanut aggulutinin, the tumor corresponded to the distal nephrons. Therefore we made the diagnosis of Bellini's duct carcinoma. She had been alive without evidence of metastases for one year after surgery.