[A malignant mixed mesodermal tumor of the ovary].

We report a primary malignant mixed mesodermal tumor in the right ovary of 75-year-old woman. She was admitted to Kobe West Municipal Hospital because of an abdominal fullness and an upper abdominal pain. A laparotomy yielded yellowish-clear ascites (2,000 ml) a tumor located in the right ovary, an upper abdominal mass the size of a child's head between the stomach and the transverse colon, and disseminating small tumors of the peritoneum. The left ovary and uterus showed no particular change. Four months after the onset of her symptoms, the patient died of carcinomatous cachexia and dyspnea. On microscope examination, the tumor of right ovary showed combined features of an adenocarcinoma, an adenosquamous carcinoma and a serous cystadenocarcinoma with foci of a heterologous stromal differentiation, that is an area of immature, striated muscle cells, bone, and cartilage and undifferentiated spindle cells. Immunohistochemical stains were useful for determining elements of the tumor cells. Epithelial tumor cells were positive for cytokeratin, epithelial membrane antigen, and CEA, while mesenchymal tumor cells were generally positive for vimentin and the immature muscle cells were especially positive for desmin, actin, and myosin. Additionally, myoglobin was identified in the rhabdomyoblast. Finally, S-100 protein was present in cartilage area and partially present in the adenocarcinomatous element.