Relapsing tumefactive demyelination lesions: A unique, distinct inflammatory brain pathology.

We report the case of a patient suffering from biopsy-proven relapsing tumefactive demyelinating lesions (TDLs) of the central nervous system who had five relapses in 16 years. No signs/symptoms suggestive of alternative pathologies emerged during the follow-up. A limited benefit was observed with intravenous (IV) high-dose steroids, while both plasma exchange and IV immunoglobulin G (IgG) administration were ineffective. A long-lasting (9 years) but transient clinical stabilization was obtained with cyclophosphamide. Our case supports the view that recurrent TDL is a relapsing brain inflammation not belonging to multiple sclerosis (MS) or myelin oligodendrocyte glycoprotein (MOG)-/AQP4-associated disorders. TDL concept and clinical features should be revised.