Epithelioid angiosarcoma of the pulmonary artery.

Pulmonary artery angiosarcoma is a rare entity. We report a case of an epithelioid angiosarcoma developing from the right pulmonary artery with pulmonary parenchymal invasion. The patient was a 69-year-old man who presented with massive hemoptysis and shortness of breath. Right middle and lower lobectomies were performed because of uncontrollable bleeding. An angiosarcoma was observed developing from the right pulmonary artery with contiguous spread down smaller artery branches with invasion of the pulmonary parenchyma. Although typical angiosarcomatous areas were observed, the neoplasm was dominated by cells with an epithelioid morphology. Immunohistochemically, the majority of cells stained for endothelial markers factor VIII-related antigen and CD34, but in addition, the cells with an epithelioid morphology stained intensely for cytokeratin. Knowledge of cytokeratin positivity in epithelioid vascular neoplasms is critical to avoid a misdiagnosis of carcinoma, particularly at sites where carcinoma is a much more likely diagnosis.