Baló Concentric Sclerosis
Baló concentric sclerosis is a rare inflammatory demyelinating disorder of the central nervous system that is often considered a variant of multiple sclerosis. It is characterized by brain lesions with a distinctive ring-like pattern of alternating areas of myelin loss and relatively preserved myelin. These concentric rings are best visualized on MRI and give the condition its name. Although it shares features with multiple sclerosis, its imaging appearance and clinical course can differ significantly.
What is it?
Baló concentric sclerosis is a demyelinating condition that affects myelin, the protective covering surrounding nerve fibers in the brain. The disease produces alternating rings of demyelination and preserved tissue, creating a target-like or onion-skin appearance on MRI. Lesions most commonly develop within the cerebral white matter and may appear as single or multiple abnormalities.
Historically, the condition was thought to follow a rapidly progressive course, but more recent studies and advanced imaging have shown that outcomes can vary considerably, with some patients experiencing partial or substantial recovery.
MRI is the preferred imaging test for evaluating Baló concentric sclerosis because the characteristic concentric ring pattern is best demonstrated on specialized MRI sequences, including T2-weighted and contrast-enhanced imaging. MRI also plays an important role in distinguishing Baló lesions from brain tumors, abscesses, stroke, and other demyelinating disorders. Additional testing, including spinal fluid analysis and, in select cases, biopsy, may sometimes be used to support diagnosis.
Important to Know
Baló concentric sclerosis can resemble brain tumors or other serious neurological conditions on imaging, making accurate interpretation by an experienced neuroradiologist especially important. Diagnosis is typically based on imaging findings together with clinical evaluation and laboratory testing.
Treatment commonly includes high-dose corticosteroids during active episodes, while longer-term immunotherapy may be considered in some patients to reduce inflammatory activity or future relapses. Follow-up MRI imaging is often recommended to monitor lesion progression, stability, or treatment response over time.
Red flag symptoms include sudden severe weakness, vision loss, difficulty speaking, seizures, rapidly worsening neurological symptoms, or loss of consciousness. These symptoms require immediate medical evaluation.