Aneurysmal bone cysts express vascular markers

Recently, clonal chromosome abnormalities have been identified in the mural spindle cells in aneurysmal bone cysts (ABCs), but the nature of the cystic spaces is unclear. Endothelial injury has been suggested as a mechanism of aneurysmal formation in these lesions, but few studies have surveyed vascular markers in ABCs. We stained 25 primary aneurysmal bone cysts with a variety of antibodies that stain vessels. Antibody to factor 8 stained the edge of ABC cavities in almost all cases, and antibodies to VEGF-C, GLUT-1, and smooth muscle actin stained the edge of the cavities in approximately half the cases. Antibodies to D2-40 and CD34 also stained the edge of the cavities in some cases. These results suggest that the cavities in ABCs are related to vasculature and support the theory that vascular injury may be important in the pathogenesis of ABCs.