Decisive role of brain biopsy in atypical tumefactive demyelinating lesions: A case report

In neuroimaging, tumefactive demyelinating lesions (TDLs), which are rare inflammatory lesions of the central nervous system, can sometimes resemble infectious or malignant processes. Radiologic distinction is frequently made more difficult by their huge size, mass impact, and contrast enhancement patterns, especially in atypical or recurrent presentations. We describe a 32-year-old woman who has several tumefactive brain lesions and recurring localized neurological impairments. On post-contrast T1-weighted images, conventional magnetic resonance imaging (MRI) showed significant periventricular, juxtacortical, and infratentorial lesions with noticeable vasogenic edema and peripheral open-ring enhancement. Susceptibility-weighted imaging (SWI) and diffusion-weighted imaging (DWI) both exhibited no blooming or actual diffusion restriction. Advanced imaging revealed moderately raised and regionally decreased perfusion on magnetic resonance imaging (MR) perfusion investigations, while MR spectroscopy revealed elevated choline ratios and a lactate peak. These results supported demyelination but were insufficient to rule out neoplastic illness. Even after partial radiological regression brought on by high-dose corticosteroids and plasmapheresis, diagnostic uncertainty persisted due to overlapping imaging results. As a result, a brain biopsy was performed, and the findings were consistent with tumefactive multiple sclerosis (MS): confluent demyelination with inflammatory infiltrates and relative axonal preservation. Histopathological evidence enabled targeted immunotherapy, which subsequently improved radiological and clinical results. This case illustrates the benefits and drawbacks of advanced neuroimaging in tumefactive demyelinating diseases, as well as the usefulness of brain biopsies as a conclusive diagnosis technique in situations where radiologic results are unclear and directly impact patient care.