Pseudotumoral rebound of multiple sclerosis in a pregnant patient after stopping natalizumab.

Natalizumab is a highly efficacious treatment for active relapsing-remitting multiple sclerosis, dramatically reducing both clinical and radiological signs of inflammation in most patients. The disease course after stopping treatment and especially the emergence of rebound activity are still a matter of debate. We present a case of dramatic reactivation of clinical disease activity with newly emerging pseudotumoral lesions in a patient who stopped treatment due to pregnancy. Both the clinical and radiological presentation suggest a rebound and necessitate close monitoring of patients stopping their treatment during pregnancy, even after a long period of stable disease.