Bilateral proliferating Brenner tumor of the ovary associated with recurrent urothelial carcinoma of the urinary bladder

CONTEXT: Brenner tumors of ovary are relatively uncommon neoplasm. Most of them are benign and less than 5% are proliferating or borderline. The association between Brenner tumor of the ovary and papillary urothelial carcinoma of bladder is extremely rare. CASE REPORT: We describe an unusual case of proliferating bilateral Brenner tumor of the ovary with a highly recurrent low-grade papillary urothelial carcinoma of bladder. CONCLUSION: The immunohistopathological similarities of ovarian and bladder tumors and their association in the current case, may be coincidental but may reflect a common initiating event inducing similar pathogenesis changes in the epithelium of both organs. More cases are needed to be reported to better understand this association.