Extravascular papillary endothelial hyperplasia of the palm masquerading as an angiosarcoma

Cutaneous extravascular papillary endothelial hyperplasia (PEH) is a rare lesion presenting as a cutaneous mass and histologically mimicking angiosarcoma. Herein, we describe a patient who presented with a palm tumor that had developed after trauma. Histologically, the lesion was ulcerated and showed proliferation of atypical epithelioid cells with nuclear enlargement and mitosis. Vascular proliferation was evident, and these were positive for CD31 and CD34, with approximately 20% positivity for MIB-1. We diagnosed this case as an extravascular papillary endothelial hyperplasia because there was no evidence of invasion into the surrounding tissue and elastica staining proved it did not have a vascular structure. To our knowledge, cutaneous extravascular PEH has not yet been reported in the published work.