Tumefactive demyelinating lesions: a case report and literature review.

Tumefactive multiple sclerosis (TMS) is a rare and diagnostically challenging variant of demyelinating disease that frequently mimics neoplastic, infectious, or vascular brain lesions. Its variable presentation often leads to diagnostic uncertainty and delayed treatment. We describe a case of a 46-year-old woman who presented with subacute neurological deficits and a large, contrast-enhancing lesion on MRI, initially suspected to be a high-grade glioma. Cerebrospinal fluid studies and advanced MRI sequences, including diffusion-weighted imaging (DWI), MR spectroscopy (MRS),were inconclusive.Histopathological examination following brain biopsy confirmed the diagnosis of TMS. The patient was treated with high-dose intravenous corticosteroids, followed by plasma exchange for steroid-refractory symptoms, resulting in partial neurological and radiological improvement. This case highlights the diagnostic complexities of TMS, emphasizing the importance of integrating advanced neuroimaging, multidisciplinary clinical assessment, and histopathological confirmation. We review recent literature on the epidemiology, radiological features, immunopathology, and evolving therapeutic approaches to TMS. Advances in MRI techniques and increased clinical awareness have improved detection, but challenges remain, especially in low-resource settings. TMS should be considered in the differential diagnosis of solitary, tumor-like brain lesions, particularly in young adults with prior demyelinating events. Early recognition and collaborative management are essential to avoid unnecessary surgical interventions and optimize patient outcomes.