Immunocytochemistry of eruptive haemangiomas (pyogenic granulomas)

Eight eruptive haemangiomas (pyogenic granulomas) were stained immunocytochemically. Many of the cells reacted with markers for endothelial cells. The reactions with anti-vWF antibody were weaker than those with UEA-I-lectin and with the monoclonal antibody BMA 120. These results probably reflect reduced capability for storage of vWF by proliferating endothelial cells. Many cells were negative for endothelial-cell markers, and they reacted with a monoclonal antibody against muscle actin. These cells may be myofibroblasts and pericytes. The studies indicate that eruptive haemangiomas are composed of pericytes, myofibroblasts and endothelial cells.