Mystery case: Baló concentric sclerosis.

A 45-year-old man presented with progressive Broca aphasia and right hemiparesis. MRI demonstrated a large white matter lesion with multiple rings (figure). These centrifugal rings reflect concentric layers of active demyelination, typical for Baló concentric sclerosis. CSF showed oligoclonal bands and a mild pleocytosis. Partial recovery followed 5 days of treatment with IV methylprednisolone (1 g daily). Baló concentric sclerosis, a rare variant of multiple sclerosis, was long thought to have a progressive and fatal course. The present case confirms the possibility of a more benign course in some cases.