Synchronous primary clear cell carcinoma of the fallopian tube: an extremely rare occurence and potential diagnostic pitfall

Primary fallopian tube carcinoma (PFTC) is by far the rarest malignancy of the female genital tract, with an incidence of 0.41 per 100000 women - but even rarer is its association with other gynecologic malignancies. In this paper we report the case of a primary clear cell carcinoma of the fallopian tube associated with a synchronous endometrioid carcinoma of the uterine corpus and discuss the main immunohistopatological aspects of both neoplasms. The difficulty of this case resides in establishing the correct diagnosis for the secondary tumor present in the fallopian tube and distinguishing between a synchronous primary tumor, a mixed endometrial carcinoma extending to the adnexa, an ovarian tumor extending to the fallopian tube or a metastasis. Moreover, we highlight the importance of always taking into consideration the diagnosis of PFTC in postmenopausal women with abnormal vaginal bleeding, when endometrial sampling and cervical biopsy are not diagnostic, even if there is no pelvic mass.