PAT-6. Malignant mixed mullerian tumor with heterologous elements arising in the fallopian tube.

Primary malignant neoplasms of the fallopian tube are rare and include carcinomas, sarcomas, and even more rarely, tumors composed of both epithelial and mesenchymal elements. Even the most common of these malignant tumors, carcinoma of the fallopian tube, accounts for less than 1% of all primary neoplasms of the female reproductive tract. Tumors with both malignant epithelial and mesenchymal elements, malignant mixed mullerian tumors (MMMTs), are very rare in the fallopian tube. Much like the more common MMMTs of ovarian and endometrial origin, MMMTs of the fallopian tube show carcinomatous elements with predominantly glandular differentiation which may assume endometrioid, clear cell, and papillary serous patterns; less commonly, squamous differentiation or undifferentiated carcinomas may be seen. The sarcomatous components of these tumors may consist of generally undifferentiated malignant mesenchymal elements, the classic homologous pattern, or any combination of skeletal muscle, smooth muscle, cartilaginous, or bony differentiation, the heterologous pattern. We report the case of a 63-year-old female who presented to our institution with complaints of abdominal swelling and discomfort. An abdominal ultrasound revealed a right adnexal mass, and a subsequent exploratory laparotomy showed a friable right adnexal mass which grossly obliterated the right fallopian tube and had disseminated widely in the pelvic and abdominal cavities. Histologic analysis of the tumor showed a neoplasm composed of a mixture of carcinomatous and sarcomatous elements, both high grade, arising in the right fallopian tube. The diagnosis of a malignant mullerian mixed tumor with heterologous elements was made. Direct extension of the carcinomatous component of the tumor was seen on adjacent pelvic structures, and metastatic carcinoma was seen in biopsies of the diaphragm and omentum. Despite aggressive chemotherapy, the patient died three months after diagnosis, illustrating the high mortality associated with these extremely aggressive neoplasms.

Elliot Carter, MD, and Tara Evans, MD. University of South Alabama Department of Pathology, Mobile, AL.