Defining the course of tumefactive multiple sclerosis: a large retrospective multicentre study.

INTRODUCTION: Tumefactive multiple sclerosis (TuMS), i.e. a MS onset presenting with tumefactive demyelinating lesions (TDLs), is a diagnostic and therapeutic challenge. We performed a multicentre retrospective study to describe the clinical characteristics and the prognostic factors of TuMS. METHODS: 102 TuMS patients were included in this retrospective study. Demographic, clinical, MRI, laboratory data and treatment choices were collected. RESULTS: TuMS was found to affect women more than men (F:M=2.4), with a young adulthood onset (median age: 29.5 years, range: 11-68, IQR: 38). At onset, 52% of TuMS patients presented with the involvement of > 1 functional system and 24.5% of them with multiple TDLs. TDLs most frequently presented with an infiltrative MRI pattern (38.7%). CSF IgG oligoclonal bands were often demonstrated (76.6%). In 25.3% of the cases, > 1 acute-phase treatment was administered. and almost a half of the patients (46.6%) was treated with high efficacy treatments. After a median follow-up of 2.3 years (range: 0.1-10.7, IQR: 3.4), the median EDSS was 1.5 (range: 0-7, IQR: 2). Independent risk factors for reaching an EDSS ≥ 3 were: a higher age at onset (OR: 1.08, 95% CI: 1.03-1.14, p<0.01); a higher number of TDLs (OR: 1.67, 95% CI 1.02-2.74, p < 0.05), and the presence of infiltrative TDLs (OR: 3.34, 95% CI 1.18-9.5, p < 0.001) at baseline. CONCLUSIONS: The management of TuMS might be challenging because of its peculiar characteristics. Large prospective studies could help to define the clinical characteristics and the best treatment algorithms for people with TuMS.