DISCUSSION
Carcinosarcomas also called malignant mixed Mullerian tumors are highly aggressive biphasic neoplasms composed of high-grade, malignant, epithelial, and mesenchymal elements. They usually occur in the uterus and rarely involve the ovaries. Most patients with ovarian carcinosarcomas are postmenopausal of low parity and older than 60 years. Our patient was a 52-year-old, nulliparous, and postmenopausal woman. Only 10% of carcinosarcomas are bilateral as it was the case in our patient. Carcinosarcomas frequently present with widespread metastases at the time of diagnosis [4]. The most common symptoms include abdominal pain, distension, nausea, vomiting, and weight loss [5]. Our patient presented with a four-month history of abdominal pain and distension. The pathogenesis of ovarian carcinosarcoma is still debated. The collision theory stipulates that the two components of the tumor are of different origin, whereas the combination theory suggests that the two components of the tumor derive from a common epithelial stem cell [6]. Some authors have reported an association between ovarian carcinosarcoma and pelvic irradiation [7]. Approximately 74 to 90% of patients with ovarian carcinosarcoma will have an elevated CA-125 as it was the case of our patient [4]. The radiological features of ovarian carcinosarcomas are non-specific and are similar to ovarian epithelial neoplasms. In the present case, ultrasonography and contrast-enhanced computed tomography scan of the abdomen revealed bilateral variegated ovarian masses with heterogeneous enhancement. Grossly, these tumors are large (mean size, 14 cm) and predominantly solid with frequent cystic degeneration and extensive hemorrhage and necrosis [8]. Histologically, carcinosarcomas are composed of high-grade carcinoma and sarcoma. One or the other may predominate. In our case, the sarcomatous component predominated. Both components are distinct but are typically intermingled with one another. The carcinomatous component is most often a high-grade serous, endometrioid, or undifferentiated adenocarcinoma and rarely clear cell adenocarcinoma or squamous cell carcinoma [8]. The sarcomatous elements are classified as homologous when the stromal component has a non-specific appearance or heterologous when rhabdomyosarcoma, chondrosarcoma (these being the most common), osteosarcoma, rarely liposarcoma or angiosarcoma are present. The presence of heterologous components can be confirmed by immunohistochemistry including desmin, myogenin and myo D1 for rhabdomyosarcoma or S100 for chondrosarcoma [8]. There is no existing consensus for the treatment of ovarian carcinosarcomas. However, the mainstay of treatment relies on optimal surgical cytoreduction followed by platinum-based chemotherapy. Combination chemotherapy with ifosfamide and cisplatin or taxol and carboplatin is favored. This results in improved progression-free survival according to large retrospective series [9]. The prognosis of ovarian carcinosarcoma is poor with a median survival reported in the majority of the studies around 11 months [10]. The adverse prognostic factors of carcinosarcomas include the presence of extra-ovarian sarcomatous elements, the advanced stage and age, the suboptimal cytoreduction, the stromal predominant tumors and tumors with serous epithelial component [8].
In conclusion, ovarian carcinosarcoma is a very rare tumor with an aggressive clinical course and a poor prognosis. The definitive diagnosis of carcinosarcoma relies on the histopathological examination of the resected specimen. The immunohistochemical study highlights the biphasic components. The present case is significant owing to the extreme rarity of this ovarian neoplasm. We must record such cases for future reference with regard to the treatment provided and the outcome achieved.