Orbitofrontal cholesterol granuloma masquerading as frontal sinus mucoceles: report of two cases

Two cases of orbitofrontal cholesterol granuloma masquerading as frontal sinus mucoceles were reported to understand image findings, clinical and histopathologic features of orbitofrontal cholesterol granuloma to improve its diagnosis and treatment.

Two East Asian patients aged 41 and 27 without personal or familial medical or trauma history presented with the common complaint of proptosis and inferomedial displacement of the eyeballs. The computed tomography (CT) of both cases showed an irregularly shaped, well-defined lesion in the left frontal bone associated with bony erosion. The lesions resulted in the bone absorption of frontal bone and orbital roof, which extended into the superior orbital space. Anterior orbitotomy through subbrow incision by drainage and curettage resulted in a curative outcome. The histopathological examination revealed inflammatory granulation tissues, fibrous capsule wall, cholesterol clefts with altered blood pigments, and calcifications, consistent with the diagnosis of cholesterol granuloma. No recurrence was observed for one year after surgery in one case and three years in the other.

When the following features are observed: orbital CT exhibits cystic lesion with irregular bone destruction in the superolateral orbit, magnetic resonance imaging (MRI) depicts lesions are hyperintense signals on T1 weighted images (T1WI), and T2 weighted images (T2WI), and the contrast-enhanced imaging reveals that the most of tumor is showed a non-significant enhancement, orbitofrontal cholesterol granuloma should be considered.