Two cases of secondary angiosarcoma arising from fibrous dysplasia.

Angiosarcoma associated with fibrous dysplasia is very rare. We have recently experienced two cases of angiosarcoma that secondarily arose from fibrous dysplasia. The first patient, a 55 year-old man, had noticed a deformity in the right upper arm since he was five years old. At the age of 25 years, polyostotic fibrous dysplasia was diagnosed by X-ray examination. The patient complained of swelling and pain around the left shoulder. The diaphysis of the humerus was mostly non-observable due to severe bone destruction by tumor invasion and there was a large soft tissue tumor. Biopsy examination revealed grade II or III hemangioendothelioma with typical histologic findings of fibrous dysplasia. After interscapulothoracic amputation for wide tumor resection, he died of DIC. Autopsy revealed multiple liver metastatic lesions of angiosarcoma. The second patient was a 66-year- old woman. She presented with a pathological fracture in the right tibia, due to an osteolytic lesion with cortical bone swelling and thinning. The histologic diagnosis was fibrous dysplasia without any sarcomatous changes. However, after a 3-time recurrence, angiosarcoma arose from the same lesion. She is now still alive with disease-free period of 6.5 years after amputation.