Abstract
Purpose: To describe two cases of arachnoid cyst that altered the bony orbit. Methods: Case report. Results: Cases of unilateral arachnoid cyst are described in two men, both over the age of 60. The patients were evaluated with computed tomography (CT) scans and in each, an arachnoid cyst in the middle cranial fossa caused bone remodeling with exophthalmos in one. These patients were followed clinically and radiographically over a number of years with no change. Conclusion: Arachnoid cysts in the middle cranial fossa have the potential to result in clinically significant proptosis due to bone remodeling of orbital walls. Patients with unexplained proptosis should be evaluated with CT scans to establish the presence of bone remodeling and an arachnoid cyst, which can be confirmed with T2-weighted magnetic resonance imaging (MRI).