Presentation
Right proptosis.
Patient Data
The MRI sequences demonstrate a well-defined right orbital mass (22 x 17 x 15 mm), surrounding the optic nerve which is displaced inferomedially. It elicits an isosignal to the cortical grey matter on both T1/T2 with vivid enhancement on postcontrast sequences. A minimal arachnoid fluid is noted between the globe and anterior margin of the tumor well-visualized on axial T2 fat sat. No extension into the optic canal is seen. There is a right axial proptosis grade I.
Case Discussion
MRI features most consistent with an optic nerve sheath meningioma with secondary axial proptosis grade I.