A Clinical Presentation of Tumefactive Multiple Sclerosis Mimicking Acute Ischemic Stroke on MRI

Abstract

Tumefactive multiple sclerosis (MS) is characterized by a magnetic resonance imaging (MRI) finding of a large, inflammatory demyelinating lesion with or without contrast enhancement. The description of non-tumefactive MS lesions is well established for a variety of MRI sequences; however, explanation of MRI characteristics for tumefactive MS lesions is limited. The findings on diffusion weighted imaging and apparent diffusion coefficient in active MS plaques are well known, but little is known about these sequences in tumefactive MS. There is data to support the use of diffusion tensor imaging (DTI) in addition to basic MR sequences when differentiating tumefactive MS from other lesions such as non-tumefactive MS plaques. The patient in this case report presented with an acute right-sided hemiparesis with a discrete hypodensity on head computer tomography, which was thought to be an ischemic stroke. The initial MRI examination showed a finding that could be consistent with ischemic stroke having decreased apparent diffusion coefficient and increased diffusion restriction. However, a subsequent MRI examination clearly revealed a demyelinating process through development of other white matter lesions. The study attempts to underline that tumefactive demyelinating disease can mimic the clinical and imaging presentation of acute ischemic stroke; therefore, cautious interpretation with clinical correlation is required for correct diagnosis.