Balo's concentric sclerosis (BCS), also known as "encephalitis periaxialis concentrica", is a dymyelinating condition which is clinically very similar to multiple sclerosis. However, MRI scans and biopsies show that lesion's in BCS form concentric rings of alternating dymyelinated and undemyelinated tissue.

Balo's concentric sclerosis is a very rare and acute condition. Unlike MS, it is most common in Chinese and Philippino populations.

Attacks of BCS procede very rapidly over weeks or months, without any remission, in a manner similar to Marburg's MS. Often these result in severe disability or death within months. More recently, however, an increasing number of cases have been reported where the disease has been self-limiting with some remission.

As with MS relapses, BCS attacks often to respond to corticosteroids, for example Methylprednisolone.

The symptoms of BCS tend to be of a more cognitive nature than with MS, including headaches, aphasia, cognitive or behavioral dysfunction and seizures but visual dysfunction, ataxia, sensory and motor symptoms are also observed.

BCS lesions are found in the central nervous system white matter of the cerebral hemispheres, cerebellum, brainstem, spinal cord, and optic chiasm. As well as demyelination, BCS also involves the destruction of the myelin producing cells, the oligodendrocytes.

Balo's concentric sclerosis links:
Balo's concentric sclerosis: clinical and radiologic features
Multiple Sclerosis Overview
Oligodendroglioma in Balo's concentric sclerosis
MRI in Balo's concentric sclerosis
Case report and MRI findings in BCS
Pathognomonic MR Imaging Findings in Balo Concentric Sclerosis

MS Glossary
All About Multiple Sclerosis