Primary ovarian fibrosarcoma: a case report and review of the literature.

Objectives: Primary ovarian fibrosarcomas are extremely rare neoplasms, and only 50 cases have been reported in the English literature. Diagnosis can be difficult because of this condition's rarity, and other similar appearing mesenchymal lesions should be ruled out.

Methods: A 50-year-old postmenopausal woman came to our hospital because of abdominopelvic pain. Ultrasonography revealed a 41x33 mm heterogeneous solid mass in the right ovary. Total blood counts, biochemical parameters, and tumor markers were within normal ranges. Total abdominal hysterectomy, and bilateral salpingo oophorectomy were performed. Examination of a frozen, specimen revealed fibroma; however, the final histopathological diagnosis was low grade fibrosarcoma of the ovary. Microscopic examination demonstrated densely cellular, spindle-shaped tumor cells with increased mitotic activity (5 to 6 mitoses per 10 high-power fields).

Results: Immunohistochemical analysis revealed that the tumor cells were positive for vimentin and negative for actin and desmin and that the Ki 67 proliferation index was 30% to 40%. The patient did not receive adjuvant treatment, and remained free of disease after a follow up of 6 months.

Conclusions: Although ovarian fibrosarcomas are unusual causes of solid masses in postmenopausal women, they should be considered when adnexal masses are examined in these patients. Mitotic activity and Ki-67 positivity were identified as important diagnostic factors for ovarian fibrosarcoma.