Abstract

Pseudomyogenic hemangioendothelioma (PH), also known as epithelioid sarcoma-like (pseudomyogenic) hemangioendothelioma, is a low-grade malignant neoplasm of endothelial origin occurring in soft tissues and bone. It is usually found in young adult males in the lower extremities. In addition to its greatest mimicker, epithelioid sarcoma, the differential diagnosis includes epithelioid angiosarcoma, rhabdomyosarcoma, and epithelioid hemangioendothelioma. Cutaneous localization of PH is rare. We present a case of a 35-year-old man with multiple long-standing raised tan-brown poorly defined skin lesions on the back and left buttock measuring from 0.3 cm to 1.7 cm in largest dimension. Excision revealed multiple ill-delineated intradermal nodules of tumor cells with a myxoid stroma. Tumor cells were arranged haphazardly or in sheets and varied from round to spindle-shaped cells with an abundance of eosinophilic cytoplasm (epithelioid-like). The nuclei were plump, with focally prominent nucleoli present. Multinucleated rhabdoid cells were seen. Immunohistochemically, the tumor cells were positive with cytokeratin, CD31, and ERB; negative with CD34 and myogenic markers. First described in 2003, PH is a low-grade malignant neoplasm, which typically recurs locally and is often confused with other malignant and benign neoplasms, especially epithelioid sarcoma. Rare cases of lymph node and distant metastases have been reported. Surgical excision is the treatment of first choice. Chemotherapy may be an option in more extensive cases, with the goal of preserving the limb.

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