Cutaneous epithelioid angiosarcoma: a clinicopathological study of four cases

Four cases of cutaneous epithelioid angiosarcoma are described together with the potential diagnostic trap of mistaking these tumours for poorly differentiated carcinoma or malignant melanoma. The immunophenotypic profile using four endothelial markers showed positive staining in all cases for factor VIII related antigen in a predominantly paranuclear dot-like fashion and for CD31 (JC70); in three cases for CD34 (QB-END/10) and in two cases with UEA-1. All four cases were cytokeratin (CAM 5.2 and AE1/AE3) negative in contrast to the positive staining reported at non-cutaneous sites. Aberrant S-100 protein expression was seen in one case. In two cases subsequent recurrences showed better differentiation than the original tumour. Electronmicroscopy confirmed the absence of non-endothelial lines of differentiation but failed to reveal Weibel-Palade bodies.