Tumefactive multiple sclerosis, a challenging diagnosis: a case report.

Case Presentation- Tumefactive multiple sclerosis (TMS) is a rare variant that presents a “mass effect” with a polymorphic clinical and radiological presentation. The objective is to report a patient with TMS and the diagnostic difficulties. Female, 42 years old, with progressive cognitive and visual deficits and headache. Investigated infection and neoplasia, treating toxoplasmosis after reagent IgG. Magnetic resonance imaging (MRI) showed tumefactive demyelinating lesions in the subcortical and bilateral periventricular white matter, with discontinuous annular enhancement. Treated with methylprednisolone and after plasmapheresis, there was a significant improvement, with control of the tumefactive lesions. Discussion- As in the literature, our case presented lesions larger than 2 cm on MRI, with mass effect, and ring enhancement in its evolution was confused with an infectious expansive process. Final comments – We draw attention to the diagnosis of TMS, which is a challenging diagnosis, often delaying treatment.