Tumefactive Multiple Sclerosis, A Rare Variant Presenting as Multiple Ring-enhancing Lesions in an Immunocompetent Patient: A Case Report

Abstract

Tumefactive multiple sclerosis (TMS) is a rare entity which can be difficult to diagnose unless definitive diagnostic measures are taken. TMS is characterized by solitary or multiple lesions that are sized > 2 cm, with/without mass effect, edema, and ring enhancement on magnetic resonance imaging (MRI). The demyelinating lesion can mimic infections, vascular lesions, and inflammatory lesions. The clinical presentation is highly dependent on the area of the brain which is affected, and this can lead to a variety of signs and symptoms. Herein, we present the case of a 40-year-old immunocompetent female with a history of right-sided numbness of her face, arm, and leg associated with muscle weakness for about a week. Workup included an MRI showing ring-enhancing lesions in the white matter of the brain, zero oligoclonal bands in the CSF, a normal immunoglobulin G (IgG) index, and an elevated myelin basic protein (MBP) in the CSF. A biopsy was obtained that showed predominant macrophage infiltrate with loss of myelin but the preservation of axons. Suspecting a demyelinating pathology, the patient was informed that she would be started on intravenous dexamethasone for an eight-day course. With subsequent completion of this course in the hospital, the patient was discharged on oral prednisone daily for a month and a referral leading to a definitive diagnosis of TMS. The patient was started on interferon beta-1a and subsequently relapsed due to noncompliance. However, further workup showed a reduction in the mass-like lesions and a response to therapy. If suspicion for TMS is high despite workup, steroids can be used with immunomodulators in the interim to combat symptoms and potentially reduce lesions and potentially subvert the need for biopsy.

Keywords: immunocompetent; immunomodulators; ms therapy; multiple sclerosis; ring-enhancing lesion; space-occupying lesion; tms therapy; tumefactive multiple sclerosis (tms).

Figure 1. Computed tomography (CT) of the head without contrast

Panel A: Displays a 2 x 1.5 cm hypodense lesion adjacent to the posterior basal ganglia/lateral thalamus. Panel B: Displays the same lesion at the level of the deep white matter adjacent to the posterior left lateral ventricle.

Figure 2. Magnetic resonance imaging (MRI) of the brain with/without contrast

Panel A: Displays a sagittal T1 image with two hypodense lesions; Panel B: Displays a T1 contrast enhanced coronal image of lesions in both cerebral hemispheres; Panel C: Displays a T2-weighted image with two (16 x 22 mm and 7 x 12 mm) periatrial ring-enhancing lesions in the left periatrial white matter; Panel D: Displays flair image of the periventricular lesion.

Figure 3. Magnetic resonance imaging (MRI) of the brain with/without contrast four months post-biopsy and treatment

Panel A: Displays sagittal T1 image with two reduced hypodense lesions; Panel B: Displays a T1 contrast-enhanced coronal image of reduced lesions in both cerebral hemispheres; Panel C: Displays a T2-weighted image with two reduced periatrial ring-enhancing lesions in the left periatrial white matter; Panel D: Displays the fluid-attenuated inversion recovery (FLAIR) image of reduced periventricular lesion. Note: Tumor dimensions on this scan were not available.