Ovarian mucinous cystadenocarcinoma with sarcoma-appearing mural nodule of anaplastic carcinoma

An ovarian mucinous cystadenocarcinoma with sarcoma-appearing solid mural nodules in an 18-year-old Japanese woman is reported. Right ovarian cyst had two poorly circumscribed, solid nodules and several tiny studs. Microscopically, the epithelial elements consisted of benign, low malignant potential and malignant mucinous tumors. The mural nodules were made up of highly malignant anaplastic cells simulating sarcoma. In one of the mural nodules, continuity between the malignant mucinous cells and sarcoma- appearing cells was identified. Immunohistochemically, the sarcoma-appearing nodule was uniformly positive for vimentin and focally positive for epithelial markers such as EMA, CAM5.2, and AE1/AE3. This case demonstrated an orderly transformation and dedifferentiation of epithelial cells to undifferentiated mesenchymal cells. Although she had stage IIb disease, she lived disease free for 3 years and 5 months after surgery followed by 10 courses of chemotherapy containing cisplatin and Adriamycin.