LAUSR

A 38-year-old woman presented with rapidly worsening, painless right monocular vision loss. An examination revealed a visual acuity of 1.4/10 and a central scotoma in the right eye. The orbital magnetic resonance imaging (MRI) showed a well-delineated ovoid intraconal mass of the right eye, hyperintense on T2-weighted MRI with homogenous enhancement after contrast injection. The mass abutted and displaced the optic nerve. A diagnosis of cavernous hemangioma was evoked, which is the most common benign adult orbital mass with these MRI features. A biopsy was performed, and the histopathologic examination yielded a diagnosis of optic nerve sheath meningioma based on a positive antiprogesterone receptor antibody immunostaining. Our case highlights the problem with establishing a specific pathologic diagnosis based on MRI alone, even though the morphologic aspect is evocative. It is recommended to always conduct a histopathologic examination before establishing a specific diagnosis as pathology remains the gold standard, especially when the course of action or treatment may change, as in our case.