Hemangioendothelioma (angiosarcoma) of bone: a distinct pathologic entity with an unpredictable course?

Eighteen cases of hemangioendothelioma (angiosarcoma) of the bone were found in a review of the files of the Department of Pathology of the Institut Curie. The ages of the patients, 11 males and seven females, ranged from 12--69 years (median 32 years). Pain was the usual symptom (11/16). Fifty percent (9/18) of the tumors occurred in the long tubular bones. Radiographic findings showed osteolytic, often multifocal, lesions without evidence of reactive bone formation. Grossly, the tumor masses were always found to be confined to the cavity of the bone. In all cases microscopic findings fulfilled the diagnostic criteria proposed by Stout. Solid and cellular small structures closely resembling embryonal vessels were observed in several instances, and were also helpful in identifying the endothelial vascular nature of the tumors. The histologic grade was difficult to determine in the majority of cases because there were several areas with different grades of differentiation. Of 15 patients with follow-up data, seven were alive and well with no evidence of disease 2--14 years after diagnosis (median nine years). Another patient was alive with metastatic disease after five years. The survival of the seven patients who died ranged from 7--53 months (median 21 months). This study confirms that hemangioendothelioma of the bone is a distinct pathologic entity. In contrast, it appears very difficult to determine the common clinical behavior of these tumors because they can show an extremely variable malignant potential.