Tumefactive multiple sclerosis: Emerging role of MR spectroscopy

Abstract

Tumefactive multiple sclerosis (TMS) is a rare variant of multiple sclerosis (MS) comprising of large demyelinating lesions that frequently mimic intracranial neoplasm or abscess. MR Spectroscopy (MRS) is an exciting new tool to differentiate radiologically. We present three cases with TMS who were diagnosed with MRS brain. A 24-years-old male presented with sensory symptoms that resolved after steroid pulse therapy. MRI spine and brain showed lesions consistent with MS and CSF showed Oligoclonal bands. Despite disease modifying therapy, he developed new symptoms. A repeat MRI brain was static and MRS showed evidence of elevated peaks of Choline and lactate with mild reduction of NAA consistent with demyelination. A 32-years-old male came for lower limb weakness and numbness with progressive gait impairment. He had history of urinary symptoms, imbalance, dizziness, ataxia and excessive fatigue. CSF analysis was normal. MRI brain revealed multiple lesions consistent with MS along with a left frontal lesion with perilesional edema and faint rim enhancement. MRS showed elevation of lactate and choline consistent with TMS. NAA was reduced. He was started on Cladribine with good response. A 37-years-old female known to have MS, on Fingolimod, developed a new relapse. MRI brain showed a left parietal cystic lesion with no contrast enhancement along with other lesions consistent with MS. MRS of the cystic lesion shows low NAA and high Choline. She was switched to Natalizumab. MR spectroscopy may serve as a helpful diagnostic tool to differentiate TMS from other counterparts.