Abstract
We present a case of a rare urinary bladder cancer. The patient was a 78-year-old lady who had a cystoscopy following an episode of macroscopic haematuria. Her endoscopic biopsy revealed a high-grade invasive carcinoma with clear cell differentiation. She underwent a radical cystectomy, which showed a clear cell adenocarcinoma (CCA) in an area of endosalpingiosis (Mullerianosis). Most bladder CCAs are not associated with Mullerianosis, have been diagnosed in patients with a previous history of urothelial carcinoma, and have an immunohistochemical profile overlapping that of usual urothelial carcinoma. They are thought to originate from glandular differentiation in urothelial neoplasms. Endosalpingiosis, fallopian tube epithelium outside the fallopian tube, is associated more with serous tumours than clear cell tumours. Although CCA of bladder has previously been called mesonephric carcinoma, there is no convincing evidence for a mesonephric origin. This case supports the postulated Mullerian origin for CCA in bladder cancer.