Malignant pleuropulmonary epithelioid hemangioendothelioma - unusual presentation of an aggressive angiogenic neoplasm.

Epithelioid hemangioendothelioma (EHE) of the lung and pleura are rare tumors. Primary pleural EHE are associated with aggressive behavior and poor clinical outcome. Recent advances in EHE include the development of immunohistochemical markers of vascular differentiation, namely Fli-1, and the identification of a specific chromosomal translocation (t(1;3)(p36;q25)). We present a 19 year old male patient with a rapidly progressive malignant neoplasm that presented as a multinodular lung parenchymal process, with associated pleural effusion and thickening. Pathologic examination revealed a pleuropulmonary neoplasm with cytologic features including round to oval epithelioid cells with frequent cytoplasmic vacuoles. Immunohistochemistry confirmed vascular differentiation of tumor cells (CD34, CD31 and Fli-1 positive). While the cytologic features were suggestive of EHE, the aggressive nature of the neoplasm, with disseminated pleuropulmonary involvement, raised the question of whether the neoplasm should be classified as EHE or epithelioid angiosarcoma. Here, we review the clinicopathologic characteristics of pleuropulmonary EHE and the overlap between malignant EHE and angiosarcoma.