Brain leptomeningeal enhancement and cranial nerve enhancement in a pediatric-onset multiple sclerosis patient during fingolimod rebound: A case report

We report a case of leptomeningeal and trigeminal nerve enhancement in an African American male patient with pediatric onset (age 17) relapsing-remitting multiple sclerosis (MS) during fingolimod rebound. The patient was clinically and radiologically stable while on fingolimod for 3.5 years, but developed disease rebound following fingolimod self-discontinuation. During this episode, several new T2/fluid-attenuated inversion recovery (FLAIR) lesions, enlarging T2/FLAIR lesions and contrast-enhancing lesions in the brain (supratentorial, cerebellum, brainstem) and spinal cord, enhancement of both trigeminal nerves and mild leptomeningeal enhancement (LME) around the brainstem were seen on brain magnetic resonance imaging (MRI). LME or cranial nerve enhancement (CNE) were not present on prior MRI studies, or on MRI studies performed after the patient recovered from fingolimod rebound. LME and CNE in MS may occur during rebound MS activity following fingolimod discontinuation as a transient phenomenon.