This is a report on a patient suffering from a progressive ulcerative tumour of the vault of the cranium with accompanying osteolytic destruction. The disease pattern was interpreted first after a biopsy from the marginal wall of the inflammation as a case of pyoderma. It was only on postmortem examination that an angiosarcoma of the ulcerative type was correctly diagnosed. The ulcerative type of angiosarcoma is sometimes difficult to differentiate from inflammatory skin diseases.