The coexistence of multiple and synchronous primary neoplasms in the genitourinary system has rarely been described in the literature. To our knowledge, this is the first report of a very rare tumor, a tubulocystic carcinoma, simultaneously occurring with micropapillary urothelial carcinoma in the bladder and clear cell type renal cell carcinoma in the same kidney. Tubulocystic carcinoma is a recently entitled tumor. It had been thought to arise from the distal collecting duct for a period of time and was therefore named as a low-grade collecting duct carcinoma. Microscopically, the tumor is defined as being tubulocystic or having tubulopapillary architecture and a low nuclear grade with hobnail morphology. Its progression and treatment protocol are uncertain.
Key Points
* Tubulocystic carcinoma of the kidney is a very rare and recently entitled entity.
* To our knowledge, this is the first report of a case of tubulocystic carcinoma occurring with conventional renal cell carcinoma of the same kidney and micropapillary carcinoma of the bladder.