Multicentric Epithelioid Angiosarcoma of Bone

Bone epithelioid angiosarcoma is rare and generally shows positive immunostaining for epithelial markers. Multicentric bone epithelioid angiosarcoma is easily misdiagnosed as carcinoma, including metastatic carcinoma, multiple myeloma, and multiple lymphoma of bone. This article describes a case of multicentric bone epithelioid angiosarcoma. The patient was first misdiagnosed as having metastatic carcinoma. Examination showed osteolytic lesions in the bilateral heels and the lower left humerus. The diagnosis was confirmed postoperatively and corrected after immunohistochemical analysis of the biopsy. The immunohistochemical analysis revealed that the tumor mass was strongly positive for CD31, factor VIII, vimentin, and neuron-specific enolase. The patient refused chemotherapy and died of lung metastasis 4 months postoperatively. Most bone epithelioid angiosarcomas are immunopositive for epithelial markers (ie, keratin, cytokeratin, high-molecular-weight keratin, and epithelial membrane antigen), vascular endothelial markers (ie, CD31, CD34, and von Willebrand factor), and factor VIII–associated antigen. Bone epithelioid angiosarcoma shows a relatively high degree of malignancy. Patients often die of distant metastasis, including those found in the lung and lymph node tissue. A wide excision of epithelioid angiosarcoma should be performed during the operation of the primary tumor. A better understanding of the clinicopathologic features of this disease may help to clarify the confusion, provide better treatment, and improve the clinical prognosis.