Childhood-onset multiple sclerosis with progressive dementia and pathological cortical demyelination

Objective: To describe a case of childhood-onset progressive multiple sclerosis with dementia and evidence of extensive cortical demyelination from brain biopsy specimen. Design: Case report. Setting: Mayo Clinic, Rochester, Minnesota. Patient: A 26-year-old man with a history of behavioral changes starting at the age of 13 years followed by progressive dementia. Interventions: Neurological examination, magnetic resonance imaging, cerebrospinal fluid studies, neuropsychological testing, and brain biopsy. Results: Magnetic resonance imaging scans showed numerousT2- weightedhyperintensitiesthroughoutthecentral nervous system not associated with contrast enhancement. Brain biopsy specimensshowedcorticalandsubcortical demyelination. All3typesofcorticaldemyelinatinglesionswere observed: leukocortical, intracortical, and subpial. Lesions were associated with profound microglial activation. The patient continued to progress despite attempts to treat with multiple sclerosis disease-modifying therapies. Conclusions: Multiple sclerosis should be considered in the diagnosis of progressivedementiain childrenandyoung adults. Cortical demyelinationmay contribute to cognitive decline in patients with dementia due to multiple sclerosis.