Background: Balo concentric sclerosis (BCS) is a rare demyelinating disease. This study aims to follow up on patients initially diagnosed with BCS and MS or presented with BCS in the context of MS.

Methods: This study was conducted at an MS clinic center in Isfahan, monitoring 2600 MS patients, among which 10 cases were related to BCS. These 10 patients were assessed clinically and radiologically during 2013-2024, with consecutive MRIs and periodic clinical examinations.

Results: Among the 10 patients, BCS was either the inaugural presentation of MS or occurred in the context of the disease. The most common Symptoms included limb weakness and paresthesia. All patients exhibited characteristic onion-like lesions in the periventricular white matter, with two showing tumefactive demyelination. CSF analysis was abnormal in all patients, revealing positive oligoclonal bands (OCB), which were categorized as type 2 in all patients. Treatment mainly involved rituximab, which indicated plausible results.

Conclusions: Our study highlights the variability in BCS clinical presentations and supports its classification as a variant of MS due to overlapping characteristics. Additionally, our findings contribute to understanding BCS's distinct clinical and radiologic profiles and emphasize the importance of further investigation into its pathophysiology and treatment.