Balo's concentric sclerosis (BCS) is a rare variant of multiple sclerosis (MS). It is named for its pattern of demyelination.


Synonym: leukoencephalitis periaxialis concentrica


The disease features rings of intact myelin alternating with rings of demyelination. The availability of MRI has improved the ability to diagnose the disorder. The histologic diagnosis can be enhanced by staining the slides for myelin.


Areas affected may include:

(1) white matter of the cerebral hemispheres (with sparing of the cortex)

(2) spinal cord

(3) optic chiasm

(4) cerebellum

(5) brainstem


The typical patient is a young adult.


Clinical features may include any combination of the following:

(1) headache

(2) aphasia

(3) cognitivie dysfunction

(4) behavioral dysfunction

(5) seizures

(6) motor dysfunction

(7) ataxia or loss of coordination

(8) sensory loss including numbness

(9) blurred vision


Examination of the CSF may show an increase in chronic inflammatory cells. Some patients may have oligoclonal bands.



(1) single episode (monophasic)

(2) relapsing-remitting

(3) primary, rapidly progressive (with death in weeks or months)


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