Bone scan and angiography for orbitofrontal cholesterol granuloma

Orbitofrontal cholesterol granuloma

Cholesterol granuloma of the orbital bones is a rare but readily recognisable condition. It is an osteolytic lesion with a granulomatous reaction surrounding cholesterol crystals, old haemorrhage and a fibrous capsule. There is a male preponderance and it usually occurs in young or middle-aged men. It is treatable with drainage and curettage via an orbitotomy, and craniotomy or wide bone removal is almost never required. Six cases of this condition were reviewed to highlight the typical clinical presentation, computed tomography and magnetic resonance results, and surgical management.

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.

Imaging of orbitofrontal cholesterol granuloma

The radiological findings in 31 patients with a histologically proven orbitofrontal cholesterol granuloma are presented. Plain films and computed tomography (CT) both show a characteristic lytic lesion allowing a reasonably confident diagnosis to be made preoperatively, thus facilitating appropriate surgery. The most important differential diagnoses on clinico-radiological grounds are lacrimal gland carcinoma and dermoid cyst. On plain films cholesterol granulomas typically show constancy of site, lysis of the superior orbital margin, frequent extension into the frontozygomatic process and absent or minimal surrounding sclerosis. On CT ragged bone destruction with a soft tissue mass no denser than brain extending extraperiosteally into the orbit are the most typical features. MRI and other imaging modalities are discussed.

Orbitofrontal cholesterol granuloma

Cholesterol granuloma of the orbital bones is a rare but readily recognizable clinical and radiologic entity usually affecting men. Twenty-seven patients are reported, and in all except one, the frontal bone in the region of the lacrimal fossa was involved. These lesions produced an area of osteolysis in the frontal bone with expansion into the extraperiosteal space of the lacrimal fossa, causing fullness of the upper lid and proptosis. The granuloma always remained extraperiosteal and was composed of a granulomatous reaction surrounding cholesterol crystals and altered blood. It is postulated that cholesterol granuloma occurs because of hemorrhage into the diploe of the bone. Extraperiosteal surgical removal cured all patients. Some previous reports have failed to identify the true nature of this lesion and confused its nomenclature.