[Intravascular bronchiolo-alveolar tumor. Study of a form with angiosarcomatous tendency].

Intravascular bronchiolo-alveolar tumor (IVBAT) is a rare pulmonary neoplasm of assumed endothelial nature. We report a new case of peculiar interest because of the association of a diffuse pulmonary involvement with multiple visceral localisations, which has scarcely been proved during life. We found out a striking endothelial differentiation on microscopic examination. The presence of F VIII RAg in many tumor cells as well as the ultramicroscopic findings support the endothelial differentiation. Thus, we regard our case of IVBAT as an aggressive form of the disease behaving as a real angiosarcoma.