Neoplastic angioendotheliomatosis (NAE) is a rare fatal disease characterized by widespread intravascular proliferations of neoplastic mononuclear cells. Clinically, dermatologic and bizarre neurologic manifestations usually predominate. The origin of the neoplastic cells remains still undetermined. The authors report a patient with NAE peculiar with respect to the following points: (1) the patient predominantly manifested respiratory symptoms and hematologic findings and lacked cutaneous or neurologic manifestations; and (2) immunohistochemical and molecular genetic studies showed the B-cell nature of the neoplastic cells, although previous cases with predominant respiratory or hematologic manifestations were reported to be of endothelial origin. Despite the rarity, this type of NAE or angiotropic [corrected] lymphoma should be recognized because it is easily confused with other disorders, particularly vasculitis or thrombotic thrombocytopenic purpura.