Mucinous adenocarcinoma of the renal pelvis associated with transitional cell carcinoma in the renal pelvis and the bladder

We report a case of mucinous adenocarcinoma of the renal pelvis associated with bladder carcinoma in situ (CIS). Transitional cell carcinoma (TCC) of the renal pelvis and CIS were also observed adjacent to the adenocarcinoma. Immunohistochemical assessment of the pelvic adenocarcinoma revealed positive expressions for mucin, epithelial membrane antigen, cytokeratin 7, cytokeratin 19 and carcinoembryonal antigen, but not vimentin or chromogranin. Based on the histopathological examinations, the adenocarcinoma of the renal pelvis in the present case may have a similar biological nature to conventional TCC and probably originated by development of pre‐existing TCC of the renal pelvis.