Collecting duct carcinoma. An unusual renal tumour

Collecting duct carcinoma is a rare form of renal tumour. Its recognition is important both clinically and histopathologically since it can mimic other renal neoplasms in appearance. Nephrectomy is the treatment of choice and, as the tumour usually pursues an aggressive course, adjuvant chemotherapy or immunotherapy may also be considered appropriate. We report two such cases.