Female Adnexal Tumor of Probable Wolffian Origin (FATWO): An Unusual Case With Development of Peritoneal Lesions After 3 Decades

Female adnexal tumor of presumed Wolffian origin (FATWO) is a rare gynecologic neoplasm favored to arise from mesonephric (Wolffian) remnants. Although most tumors are benign, rare recurrences have been reported. Herein, we present a case of a 65-year-old female with incidental peritoneal lesions detected on routine ultrasound that morphologically and immunohistochemically were diagnostic of FATWO. Review of her medical history uncovered a remote history (>30 years) of a para-ovarian cystectomy, which was punctured intraoperatively. Slide review confirmed the diagnosis of FATWO, thereby suggesting iatrogenic dissemination from the original procedure. This report highlights the importance of a thorough review of the medical record when encountering a nonprototypical location for a distinctive tumor. In addition, the slow-growing nature of these lesions, as well as the absence of atypical histologic features, further contributes to the hypothesis that the majority of FATWOs are benign.