Primary epithelioid hemangioendotheliomas and angiosarcomas of the pleura: a clinicopathological and immunohistochemical analysis of 13 cases.

Thirteen cases of primary epithelioid hemangioendotheliomas (EHE) and epithelioid angiosarcomas (EA) of the pleura are presented. The patients were 7 men and 6 women between the ages of 34 and 65 years (mean: 47 years). The patients presented with non-specific symptoms of cough, dyspnea, and chest pain. Diagnostic imaging revealed the presence of either diffuse pleural thickening or pleural nodules involving the serosal surfaces. Open surgical biopsies were obtained in all cases. Histologically, eight tumors were characterized by the presence of a cellular proliferation composed of medium-sized epithelioid cells embedded in a myxohyaline stroma and a variable spindle cell component. Cellular atypia was mild to moderate and mitotic activity ranged from 1 to 2 per 2 mm2. Immunohistochemical stains for vascular markers, including CAMTA1 were positive, confirming a diagnosis of EHE. Five cases of epithelioid angiosarcomas were characterized by a neoplastic cellular proliferation admixed with areas of necrosis and hemorrhage and characterized by medium-sized epithelioid to spindle-shaped cells with eosinophilic cytoplasm, round to oval nuclei and prominent nucleoli. In addition, marked cytologic atypia and a mitotic activity ranging from 3 to 5 per 2 mm2 were identified. Immunohistochemical studies demonstrated positive staining for vascular markers; however, CAMTA1 was negative. Clinical follow-up obtained in eleven cases showed that all patients had died within 30 months post diagnosis. The current study highlights that even though it may be important to histologically separate EHE from EA for academic purposes, primary pleural origin of these tumors appears to portent an aggressive clinical behavior.