[Balo's concentric sclerosis].
Balo's concentric sclerosis (BCS) is a rare demyelinating disease, first described by Hungarian neurologist Josef Balo in 1928. BCS occurs predominantly in young adults, the average age of onset of the disease - 34 years (range from 3 to 62 years). Our case report describes a 27-year woman with acute onset progressive right-side pyramidal weakness, MRI results showed a variant of demyelination as Balo's concentric sclerosis.