Pathogenesis of orbital cholesterol granuloma.

Two cases are presented of orbital cholesterol granuloma associated with gradual proptosis arising in men aged 35 and 41 years. Computed tomography demonstrated osteo-lytic masses in the frontal bone at the lacrimal fossa. Curettage revealed a characteristic histology of foreign body reactions surrounding cholesterol clefts. In both cases abnormal bone, more consistent with fibrous dysplasia than reactive change, was found at the periphery. The finding of abnormal bone associated with orbital cholesterol granulomas suggests that a pre-existing bone anomaly may be present in a subset of these cases.