Retiform hemangioendothelioma (RH) is a rare vascular neoplasm most often occurring in the limbs of middle-aged females. This entity is characterized by infiltrative vascular spaces arranged in a pattern similar to the rete testis. RH differs from angiosarcoma by lacking cytologic atypia and high mitotic rates. This neoplasm frequently recurs but rarely metastasizes. RH tumor cells react with vascular endothelial markers CD31, CD34, and factor VIII-related antigen. A review of the English literature provides only one attempt at staining RH with D2-40, a marker of endothelium of lymphatic vessels, which was negative, and one reported staining of RH with lymphatic endothelial marker VEGFR-3, which was positive. The etiology of RH is unknown. RH has previously been considered closely related to Dabska tumors, which are positive for lymphatic endothelial marker D2-40. We stained 4 RHs with mouse monoclonal antibodies against D2-40 and CD31 and 3 of the 4 RHs with vascular endothelial growth factor receptor 3 (VEGFR-3), to further evaluate whether RH had lymphatic differentiation, in addition to vascular differentiation. Three of the 4 RH biopsies failed to demonstrate D2-40, none expressed VEGFR-3, whereas CD31 was strongly positive, suggesting that RH is a vascular entity which usually does not have lymphatic differentiation, but may rarely express D2-40.