Primary angiosarcomas of the anterior mediastinum: a clinicopathologic and immunohistochemical study of 9 cases.

We report 9 cases of primary angiosarcomas of the anterior mediastinum. Patient ages ranged from 25 to 62 years (mean, 40.7 years); 5 patients were male and 4 were female. Main presenting symptoms included chest pain, dyspnea, and cough. The tumor size ranged from 3 to 12.5 cm. Macroscopically, the lesions were ill-defined hemorrhagic masses. Histologically, the growth patterns ranged from large vascular spaces to capillary-like proliferations. These were either lined by bland or more pleomorphic endothelial cells. The mitotic activity was variable and corresponded to the degree of differentiation. A rim of thymic tissue was observed in 2 cases suggesting a thymic origin of the tumors. No teratomatous components were identified. Immunohistochemical studies showed that all 9 cases were reactive for vascular markers including factor VIII-related antigen, CD31, and CD34, and negative for cytokeratin CAM5.2. All cases were treated by complete resection and 3 patients received adjuvant chemotherapy. Follow-up information available for 6 patients revealed that 4 were alive and free of disease at intervals ranging from 6 to 36 months after diagnosis and 1 was alive with recurrence at 48 months. One patient had died of the disease 10 months after diagnosis. Primary angiosarcomas of the anterior mediastinum are rare tumors that need to be added to the differential diagnosis of primary anterior mediastinal neoplasms. Despite their histologic similarity to angiosarcomas at other sites, primary angiosarcomas of the anterior mediastinum appear to follow a more protracted clinical course than their counterparts in other organ systems.