Endometrioid carcinoma of the fallopian tube resembling an adnexal tumor of probable wolffian origin: a case of report and review of the literature.

Endometrioid carcinoma is a common tumor of the female genital tract, mainly affecting the uterus corpus and ovary. In the fallopian tube, endometrioid carcinoma is relatively uncommon. The female adnexal tumor of probable wolffian origin (FATWO), although occasionally seen elsewhere, is most typically encountered in the broad ligament. Endometrioid carcinoma of the fallopian tube resembling FATWO is a rare type of endometrioid carcinoma, and only 20 cases have been reported to date. Here, we report a case of endometrioid carcinoma of the fallopian tube resembling FATWO and review the literature. A 67-year-old woman presented with a history of prolapse for about one month outside the vulva. Physical examination and pelvic ultrasonography of the patient revealed a streak mass covering the left ovary. A total hysterectomy and a bilateral salpingo-oophorectomy were performed. The tumor was confined to the tube and strongly resembled FATWO. Immunohistochemically, the tumor cells were positive for AE1/AE3, epithelial membrane antigen (EMA), and p16, but negative for CD10, inhibin-alpha, calretinin, vimentin, myogenin, and desmin, CD99,CgA, and Syn. We review the previously published cases of endometrioid carcinomas of the fallopian tube resembling FATWO, and discuss the principal differential diagnosis of the tumor in the fallopian tube.