OBJECTIVETo study the clinicopathological features of epithelioid angiosarcoma (EA) and to propose its differential diagnosis.

METHODS15 EAs were observed by means of HE staining, immunohistochemical staining (ABC method) and in part by electron microscopy.

RESULTSTwelve cases occurred in men and three in women. Clinical symptoms included a focal mass with pain, weight loss and weakness. The tumors were located in the retroperitoneum (n = 3), extremities (n = 3), femur (n = 4), thyroid (n = 2), supraobit (n = 1), soft tissue of thorax (n = 1), soft tissue of neck (n = 1). Radiographic evaluation demonstrated solid to cystic neoplasms ranging from 3 to 20 cm in diameter. Histologically, the epithelioid cells were arranged diffusely or in nests with hemorrhage and focal necrosis. Atypical tumor cells lined the irregular spaces and single or small nests of cells grouped around a lumen containing red blood cells. FVIII, CD34, CD31,CK and EMA were positive in tumor cells and SMA was positive in pericytes. Ultrastructurally, intracytoplasmic vacuoles, Weibel-Palades, intermediate filaments and basal lamina could be seen. Surgical resection was the treatment of choice, occasionally with adjuvant chemotherapy. Follow-up. Two patients are presently alive 19 months and 7 years following diagnosis. Twelve died from 2 weeks to 38 months with a median interval of 19 months after lumpectomy. One patient was lost to follow up. There were 8 cases which had metastases to lungs, bones, lymph nodes and abdominal cavity.

CONCLUSIONSEA is a high-grade sarcoma. Endothelial derivation can be confirmed by immunohistochemical staining and ultrastructural findings. The differential diagnosis of EA includes metastatic carcinoma, epithelioid hemangioendothelioma, melanoma, epithelioid sarcoma etc.