Epithelioid angiosarcoma of the skin: a study of 18 cases with emphasis on its clinicopathologic spectrum and unusual morphologic features.

We report 18 cases of cutaneous angiosarcoma with predominant or exclusive epithelioid morphology. Both sexes were similarly affected. Patients' ages ranged from 2 to 97 years, median 77.5 years; 2 were pediatric patients. In elderly patients scalp or facial lesions and cutaneous lesions arising within irradiated breast skin predominated. Limb lesions were seen in younger patients. Microscopically, the tumors were composed of packed polygonal cells with focal evidence of endothelial differentiation. Diverging phenotypes included syncytial growth of large cells with clear nuclei and prominent nucleoli, micronodules of tumor cells scattered in dermis, predominance of discohesive plasmacytoid polygonal cells with abundant bright eosinophilic cytoplasm, sheets of clear cells with coarse granular cytoplasm, trabecular and cord arrangement of tumor cells splaying the dermal collagen, or a pseudoglandular appearance owing to clear cell tubular arrangement with open lumina. These cases posed further diagnostic challenges simulating lymphoma, melanoma, lymphoepithelioma-like carcinoma, adnexal carcinoma, and neuroendocrine carcinoma. Immunohistochemical studies showed positivity for CD31 and CD34; no immunoreactivity was documented for other tested antigens including cytokeratins, S100 protein, melanocytic antigens, leukocyte common antigen, and desmin. Therapeutic modalities included combined local excision, chemotherapy, and radiotherapy, depending on patient clinical status. Of the 9 patients available for follow-up, 5 were alive and apparently well, 2 had recurrent disease, and 2 had died of tumor. Our data show that epithelioid cutaneous angiosarcoma may have a broad morphological spectrum, raising interpretive challenges on microscopy. In addition, its clinical presentation seems to differ in nonelderly patients, with lesions likely related to lymphedema or vascular malformations.