Angiosarcoma developing in an ovarian fibroma: A case report.

Angiosarcomas are malignant vascular tumors primarily located in the dermis or soft tissues predominantly in the head and neck region. Ovarian localization is extremely rare, with only a few published cases. A 63-year-old patient was admitted to the hospital due to severe pain in the hypogastric and abdominal regions. The condition was interpreted as an acute abdomen and referred to surgery, and an ovarian tumor that measured 23cm×11cm×5cm and weighed 7500g was resected. Macroscopically, the cut surface showed two well-defined areas: one consisting of a matte white tissue with a fascicular appearance and firm consistency and the other hemorrhagic with necrotic areas. Histological examination revealed two patterns: one characterized by a proliferation of spindle-shaped cells without atypia, and the other by neoplastic proliferation with marked atypia, forming vascular channels or fascicles. The vascular component was positive for CD31, CD34, and ERG. The findings were interpreted as an angiosarcoma associated with a fibroma, and the patient died in the immediate postoperative period. The low incidence and ominous prognosis of primary or metastatic ovarian angiosarcomas have been confirmed. Regarding the histogenesis, a strong likelihood exists of a relationship with the ovary's rich vascular network. In both well-differentiated and poorly differentiated cases, it is crucial to consider differential diagnoses and perform immunohistochemical techniques, which can assist in achieving an accurate diagnosis. The association between fibroma and angiosarcoma is poorly understood and the histogenesis remains unclear.