[Cutaneous angiosarcoma with difficulty in differential diagnosis of thrombocytopenia].

An 87-year-old man was referred to our hospital because of sustained bleeding from head skin lesions after trauma. Examination of peripheral blood showed severe thrombocytopenia, a nearly normal coagulation test, and elevated PAIgG. Based on the tentative diagnosis of immune thrombocytopenic purpura (ITP), immunosuppressive drugs and high-dose immunoglobulin were administered; however, the platelet count did not recover, and was followed by severe DIC, resulting in a fatal outcome due to massive bleeding from the scalp. Histopathological examination of autopsy samples of skin lesions revealed angiosarcoma, suggesting that Kasabach-Merritt syndrome (KMS) complicated with DIC, but not ITP, was the primary cause of thrombocytopenia. Although KMS is commonly accompanied with hemangioma in infants, it is extremely rare in patients with angiosarcoma, which is an uncommon malignant neoplasm. In this case, our correct diagnosis of thrombocytopenia was difficult because of the unusual clinical setting, indicating that careful interpretation of physical, laboratory and pathological examinations is mandatory for correct diagnosis of thrombocytopenia of unknown etiology.