MALIGNANT MIXED MULLERIAN TUMOR (MMMT) PRESENTS AS A RETRO-RECTAL MASS: A CASE REPORT.

Anthony Dakwar, MD, Melissa S Zoumberos, MD, Alexandria Glenn, MD, Sowsan Rasheid, MD. University of South Florida, Tampa General Hospital

Malignant Mixed Mullerian Tumors (MMMT) are a rare and aggressively malignant cancer of the female genital tract, usually arising from the uterus, cervix, and ovaries. MMMT are considered a carcinosarcoma, due their histological characteristics of both epithelial cells as well as connective tissues. Prognosis is mainly poor, even after appropriate surgery and adjuvant therapy treatments. We report a case of a MMMT having an unusual presentation as a retro-rectal tumor.

MMMT are mostly consistent with a history of vague abdominal pain and associated vaginal bleeding. These tumors can grow to a substantial size and encompass the entirety of the abdominal compartment, as an intra-peritoneal mass. The patient we are presenting complained of vague perineal pain along with a radiculopathy to her right leg. Physical exam revealed an enlarged right buttock, with mass effect along with erythema and skin-dimpling (Figure 1). The abdominal and pelvic exams were normal. Vaginal ultrasound and computed tomography (CT) did not illustrate the origin of this tumor, only confirming it location in the pre-sacral space tracking into the her pelvic organs. Magnetic resonance imaging (MRI) was obtained to further characterize the mass. It showed a 16x11x12 centimeter heterogenous mass with cystic components, hyper-intense on T2 weighted image (Figure 2). Tumor markers and other lab work were unremarkable.

The patient underwent a retro-rectal tumor excision via Kraske approach. The tumor appeared to be involving the uterus and base of the cervix at the time of surgery, requiring a trans-abdominal approach to adequately remove it and all its components. Patient recovered well and discharged home. Pathology revealed that the tumor was indeed a MMMT, arising from polypoid endometriosis.

In conclusion, we report a case of a Malignant Mixed Mullerian Tumor that presented in the pre-sacral space. Tumors of gynecological origin are known to occur in the retro-rectal space, however such a rare pathology as MMMT usually is limited to the peritoneal cavity. A high index of suspicion must be maintained during the evaluation of giant retro-rectal tumors that are found to be heterogenous with multiple cystic components on pre-operative imaging. The extent of disease in this case and its unusual location is indicative of the potential for aggressive endometrial transformation and migration.

Figure 1. Physical exam findings of right buttock.