Transitional cell carcinoma of the endometrium associated with benign ovarian brenner tumor: a case report with immunohistochemistry molecular analysis and a review of the literature.

Transitional cell carcinoma of the endometrium (TCCE) is a subtype of endometrial carcinoma, characterized by a prominent papillary pattern, resembling the papillary carcinoma of the urothelium. This neoplasm is very rare, with only 13 cases reported in the international literature. In this paper, a new case of TCCE associated with benign ovarian Brenner tumor is described. This association is extremely rare, with only 1 other case reported. A review of the literature is performed to delineate the clinico pathologic features of this malignancy. Moreover, immunohistochemical and molecular studies are carried out in the effort to establish the phenotype and etiology of this rare neoplasm. The molecular study, by polymerase chain reaction (PCR) failing to reveal the presence of HPV DNA, demonstrates that neither the TCCE nor the ovarian Brenner tumor is caused by an HPV infection. The association of TCCE with benign ovarian Brenner tumor could be a coincidental event. Conversely, this finding could be the manifestation of a multicentric metaplastic process (neometaplasia), involving both the coelomic epithelium of the ovary and the Mullerian epithelium of the uterus, or the evidence of "field effect" that manifests differently at different anatomical sites. In our view, other cases of TCCE associated with ovarian Brenner tumor should be reported to confirm the last 2 hypotheses.