285 An Uncommon Presentation of Extragenital Carcinosarcoma

Abstract

Carcinosarcoma, or malignant mixed Müllerian tumor, comprises less than 5% of all uterine malignancies. It is extremely uncommon to diagnose carcinosarcoma outside of the genital tract. Here, we present a 56-year-old woman who was being evaluated for an endometrial polyp. Endometrial curettage was performed. Microscopy showed fragments of an endometrial polyp with focal well differentiated endometrioid endometrial carcinoma, arising in a background of complex endometrial hyperplasia with atypia. She then underwent a total hysterectomy with bilateral salpingo-oophorectomy. Histological evaluation revealed a well differentiated endometrioid adenocarcinoma limited to the endometrium, with no protrusion into the uterine wall, extension into the adnexae, or lymphovascular invasion. At nine months status post total hysterectomy, the patient presented to her clinician with new onset vaginal bleeding, rectal bleeding. Radiological investigations revealed two 7 cm pelvic masses. Biopsy of the mass revealed highly atypical glands in a desmoplastic stroma and necrosis with features consistent with adenocarcinoma of Müllerian origin. Given the recent history of endometrial adenocarcinoma, the mass was suspected to have an endometrial origin. An exploratory laparotomy with resection of the pelvic mass, omentectomy, pelvic and para-aortic lymphadenectomies, low anterior bowel resection, ileo-cecectomy, partial vaginectomy, and left parametrial resection was performed. Histological evaluation demonstrated a fragmented carcinosarcoma; the carcinomatous component comprised predominantly endometrioid carcinoma and the sarcomatous component comprised endometrial stromal sarcoma. All lymph nodes were negative for malignancy. Immunohistochemical studies confirmed the morphological findings. Extensive sampling of the mass also showed foci of endometriosis. We present this case to highlight that a high index of suspicion and attention to morphologic details are paramount to arrive at an accurate diagnosis. It is most likely that the carcinosarcoma arose from the endometriosis rather than metastatic deposits from the previously known primary endometrioid carcinoma.