Primary osteosarcoma of the uterine corpus: Report of a case with immunohistochemical and ultrastructural study

Background. Primary uterine osteosarcoma is extremely rare, with only 15 ca ses reported in the literature. Case. A 41-year-old woman presented with abnormal vaginal bleeding due to a large tumor arising from the uterine corpus. Histologically, the tumor sho wed the features of a malignant mesenchymal neoplasm with osteoid formation and lacked an epithelial component. Immunohistochemical and ultrastructura l studies showed no evidence of epithelial differentiation. The tumor was e xcised and the patient received chemotherapy and radiation therapy postoper atively, but the tumor recurred locally at the 8-month follow-up. Conclusion. Osteosarcoma as a primary uterine tumor is exceedingly rare and should be distinguished from carcinosarcoma, which shows different macrosc opic and histologic features, Prognosis of this neoplasm is very poor with an average life expectancy Of 5 months. (C) 2001 Academic Press.