Carcinosarcoma is a malignant tumor that is composed of epithelial and mesenchymal components. It occurs most frequently in the uterus as malignant Mullerian tumors, endometrioid adenocarcinomas (EA) or a highly atypical carcinoma of the uterine corpus uteri (CAC). It is also found in other anatomic sites such as the lungs and stomach and is occasionally encountered in the skin. Despite the relatively infrequent occurrence of this tumor, it is amongst the leading gynecologic neoplastic malignancies due to its highly aggressive clinical behavior and high mortality rates. Carcinosarcoma is often confused with other tumors such as conventional carcinomas and metastatic sarcomas, so the identification of these features requires careful pathologic evaluation.
The etiology of carcinosarcoma is not completely understood. Several theories have been advanced, including the monoclonal theory, which proposes that undifferentiated, totipotential cancer cells differentiate into histologically recognizable epithelial and mesenchymal tumor components, and the multiclonal theory, in which epithelial and mesenchymal elements arise independently from different cancer stem cell populations. Both tumor components have been shown to display chromosomal abnormalities, with the most consistent finding being allelic loss of chromosome 9p in both carcinomatous and sarcomatous tumor cells.
A 52-year-old female presented with heavy irregular menstrual bleeding for several years and a new right elbow pain and swelling. Ultrasound and computed tomography revealed a large uterine mass with regional and distant lymphadenopathy and osseous metastasis to the right elbow. Biopsy of the uterine lesion confirmed carcinosarcoma. Molecular studies identified an ARID1A mutation and an absence of p53 in the carcinomatous component and a vimentin expression pattern in the sarcomatous component that suggested endometrioid differentiation.
This patient underwent surgical resection of the uterus with subsequent chemotherapy and adjuvant radiation. She had a good response to treatment and was referred for surveillance by gynecologic oncology and gastroenterologists. In addition to regular pelvic CT, she has undergone whole abdominal radiation and three cycles of ifosfamide plus cisplatin. She is scheduled to have additional chemotherapy as part of a GOG 150 phase III trial for recurrent or metastatic uterine CAC.
