Kasabach-Merritt syndrome (KMS) describes a consumptive coagulopathy associated with certain vascular tumors. It is thought that platelets are destroyed as they circulate through the aberrant endothelial surfaces associated with these tumors. Most published literature describes infants with kaposiform hemangioendothelioma, but a similar syndrome can complicate angiosarcoma in adults. This report describes a man with metastatic angiosarcoma arising in the scalp in whom disease progression was complicated by profound thrombocytopenia consistent with KMS. His disease and associated KMS had progressed previously through paclitaxel and then through liposomal doxorubicin. It did not respond to paclitaxel and bevacizumab, but responded almost completely to chemotherapy with gemcitabine and vinorelbine. Six months later, progression through ongoing chemotherapy then responded to chemotherapy with cyclophosphamide and sirolimus.