A renal cancer with intermediate characteristics between collecting (Bellini) duct carcinoma and urothelial carcinoma: case report and review of the literature.

Collecting duct carcinoma of the kidney is a rare and aggressive neoplasm of the distal collecting tube, often metastatic at the time of the diagnosis, for which there is no established therapy. We herein describe the case of a 65-year-old man with a renal cancer with a particular immunohistochemical pattern and pathologic aspect. The lesion was diagnosed as a tumor borderline between a urothelial carcinoma with intraductal spreading and a collecting duct carcinoma with calyceal and pelvic spreading. The patient is disease-free 11 months after diagnosis, after radical surgery with adjuvant chemotherapy (carboplatin and gemcitabine) and radiotherapy of a local recurrence. Owing to the common embryologic origin of collecting duct and transitional urothelial cells, several authors have reported an association between collecting duct carcinoma and urothelial cancer. The literature is reviewed to evaluate drugs active against urothelial cancer (like ifosfamide, paclitaxel, carboplatin and gemcitabine). This field should be investigated in the future, in the framework of a neoadjuvant or adjuvant chemotherapy able to support radical surgery for local and advanced collecting duct carcinoma.