IMMUNOHISTOCHEMICAL AND ULTRASTRUCTURAL EVIDENCE OF A MODIFIED MICROVASCULATURE IN THE GIANT-CELL GRANULOMA OF THE JAWS

A panel of five immunohistochemical markers, MB1, leukocyte common ant igen, S-100 protein, smooth muscle specific actin, and factor VIII rel ated antigen, were used to study 20 giant cell lesions. These included eight central giant cell granulomas, nine peripheral giant cell granu lomas, and three giant cell tumors of bone. The multinucleated giant c ells stained positively with MB1, the mononuclear round cells were pos itive to leukocyte common antigen and the spindle cells were unreactiv e to all the markers chosen in all the lesions. The most interesting f inding was the staining pattern of the blood vessels to factor VIII re lated antigen in the giant cell granuloma. The blood vessels on the pe riphery of the lesions were strongly positive for this antibody. Howev er, reaction product was not evident deeper in the lesion within the a ggregations of giant cells. Two other endothelial cell markers, Ulex e uropaeus 1 lectin and QBend 10 were used to study 10 giant cell lesion s and a similar pattern of staining was observed. Transmission electro n microscopy was subsequently used to study the ultrastructure of the microvasculature of three peripheral giant cell granulomas, and the fi ndings indicated that the reasons for the differential staining may li e in the differences in the structure of the microcirculation.