Usefulness of D2-40 immunohistochemistry for differentiation between kaposiform hemangioendothelioma and tufted angioma

Background:Recent investigations have demonstrated the utility of the monoclonal antibody D2-40 as a marker for lymphatic endothelium. D2-40 can be used on formalin-fixed and paraffin-embedded materials. Our objective was to elucidate, using D2-40 immunohistochemistry, the differences among capillary hemangiomas, and especially between kaposiform hemangioendothelioma (KHE) and tufted angioma (TA). We studied four cases of KHE, nine cases of TA, and 31 cases of other vascular tumors. Antibodies against CD31, CD34, factor VIII-related antigen, and GLUT1 were also applied. Results:In KHE, D2-40 was markedly reactive for three and partially for one of four cases in the peripheral area of Kaposi's sarcoma-like proliferative capillaries and negative in the surrounding dilated vessels. In TA, D2-40 was partially positive in the surrounding dilated vessels and negative in cannonball-like proliferative capillaries. Conclusions:Our results suggest that D2-40 is a useful antibody for immunohistochemical discrimination between KHE and TA. In addition, the difference of immunostaining pattern of D2-40 is limited to the peripheral area of capillary proliferation and surrounding dilated vessels; therefore, it is suggested that KHE and TA may reflect different stages in the evolution of a single entity. Namely, they may originate from stem cells possessing the characteristics of both lymphatic and blood vessel endothelial lineages.