Tumefactive multiple sclerosis: a case report and review of the literature.

Tumefactive multiple sclerosis (TMS) is a rare subset of inflammatory demyelinating disorders that can present with MS symptoms or the clinical or radiographic findings of a space-occupying intracranial lesion. Classically, TMS presents on computed tomography (CT) or magnetic resonance imaging (MRI) with an intracranial mass greater than 2.0 cm with a variable amount of mass effect, edema, and ring or rim enhancement with gadolinium contrast. Unfamiliarity with this condition may lead health care providers to perform unnecessary biopsies or delay proper treatment. We present the case of a patient who came to the emergency room with bilateral internuclear ophthalmoplegia who was later diagnosed as TMS.