Pseudo-Cerebrospinal Fluid Sign on Magnetic Resonance Imaging in a Patient with a Presumed Optic Nerve Sheath Meningioma

Abstract

A 45-year-old man developed visual loss in the right eye, associated with clinical evidence of an anterior optic neuropathy. Magnetic resonance imaging showed an enlarged right optic nerve shadow with changes suggesting accumulation of cerebrospinal fluid (CSF) surrounding the orbital portion of the nerve; however, ultrasonography revealed solid thickening of the nerve, and a diagnosis of presumed optic nerve sheath meningioma (ONSM) was made. The “pseudo-CSF sign” has been well-described in patients with optic nerve gliomas in the setting of neurofibromatosis; however, to our knowledge, it has not been described in patients with ONSMs.

Keywords:

• optic nerve
• meningioma
• magnetic resonance imaging
• pseudo-CSF sign