BACKGROUND: A tumefactive demyelinating lesion (TDL) is an area of pathological changes in the central nervous system consistent with demyelination, larger than 2 cm, and can mimic tumors on imaging; hence the term "tumefactive." TDLs are often challenging, as they have been reported in isolation or in conjunction with demyelinating diseases. OBJECTIVES: To describe the clinical and radiological features of TDLs, explore the treatments used and outcomes, and describe different nomenclatures reported. METHODS: We followed PRISMA guidelines, and our protocol was registered on PROSPERO CRD42024593078. We searched PubMed, Web of Science, EMBASE, and Google Scholar. We included published cases with TDL (> 2 cm) on magnetic resonance imaging (MRI) in patients aged ≥ 18 years. We excluded a priori any established diagnoses of the lesions other than TDLs, cases without biopsy confirmation of demyelination, and cases lacking relevant data. The study framework is exploratory and descriptive in nature, and analyses are taken as hypothesis-generating. Comprehensive Meta-Analysis V3.0 was used for meta-analyses. RESULTS: = 62.4%), which should be interpreted cautiously given the small number of contributing studies. Subgroup analysis revealed no meaningful differences between nomenclatures. Publication bias assessments were exploratory and suggested potential bias, and that the observed variability may reflect study-level and reporting differences rather than disease-related effects. CONCLUSION: Acute IVMP treatment had a high response rate and similar use rate. Despite variations in nomenclature and presentation, the broader pathological and clinical features, as well as the response to IVMP in TDLs, appear broadly similar across studies, acknowledging the methodological limitations of the available literature. Our study was also limited by the small sample due to the rarity of the condition.
Alaskar et al. (Mon,) studied this question.