Pseudomesotheliomatous angiosarcoma: a pleuropulmonary lesion simulating malignant pleural mesothelioma

We report two cases of autopsy confirmed angiosarcoma in adult males, presenting as diffuse pleuropulmonary tumours and simulating malignant mesothelioma. Both the lesions grew along the serosal surfaces and were characterized by variably thick rinds of tissue encasing the lung. The pulmonary parenchyma showed diffuse, dark red, subpleural consolidations and multiple cavitations. Histologically, the lesions were composed by atypical spindle and polygonal, epithelioid cells showing rudimentary vascular differentiation and exhibiting strong positivity for factor VIII, CD31, CD34 and vimentin. We conclude that angiosarcoma may present with preponderant or exclusive involvement of pleura and peripheral lung and that it should be added to the list of tumours capable of simulating malignant mesothelioma.