Emerging tumefactive MS after switching therapy from interferon-beta to fingolimod: A case report.

We describe a case of tumefactive multiple sclerosis, based on characteristic imaging features and excluding alternative diagnoses, presented with relapse 18 weeks after switching betaferon to fingolimod. Recent reported cases of this paradoxical demyelinating reaction in a setting of fingolimod-related immune system alterations seem to be something more than an accidental event. Immune cell shifting underlying a genetic susceptibility factor has been suggested to participate in this disastrous adverse effect. It could be a warning sign which physicians should take it into account for better recognition of patients at risk and select candidates for this management.