Last updated:
9/24/2025
Years published: 1986, 1994, 2003, 2007, 2025
NORD gratefully acknowledges Gioconda Alyea, MD (FMG), MS, National Organization for Rare Disorders for assistance in the preparation of this report.
Summary
Balo disease or Baló’s concentric sclerosis (BCS) is a rare type of multiple sclerosis (MS). MS is a disease where the immune system attacks the protective covering (called myelin) of nerves in the brain and spinal cord. In BCS, this damage appears in concentric rings, meaning circular layers of healthy and damaged tissue in the brain’s white matter. These patterns are often described as looking like a “tree trunk” or “onion bulb” on brain scans.1
Signs and symptoms may include cognitive problems, headaches, muscle spasms, paralysis or weakness on one side of the body (hemiplegia), numbness or loss of sensation (hemianesthesia) and coordination difficulties (ataxia).1,2 The radiologic presentation resembles brain tumors.1-3 When MRI brain scans show concentric ringed lesions, doctors must consider this diagnosis, even in children.3,4
Although BCS shares similarities with regular MS, it is different in how fast it progresses.2 While MS may come and go (relapse and remission), BCS often gets worse quickly.2
The cause of BCS is still unknown but it seems to be autoimmune.
Treatment may involve medication such as corticoids and procedures such as plasmapheresis.3-6
BCS was once considered a rapidly fatal condition, but this is no longer always the case. Some people recover fully or have long-term remission, especially when diagnosed and treated early.2,3 Other cases may progress slowly over years.
Introduction
BCS is a rare type of multiple sclerosis (MS) named after Dr. József Balo and first described by Marburg in 1906. In the past, BCS could only be diagnosed after death through autopsy findings that revealed distinct patterns of damage in the brain known as demyelinating lesions. Today, diagnosis is possible during a person’s lifetime using a combination of clinical evaluation and imaging techniques.7
BCS can appear in one of three main forms, a short-term type that resolves on its own, a pattern of symptoms that come and go, or a rapidly worsening form. The symptoms a person has often depend on where the disease affects the central nervous system. In some people, symptoms may develop suddenly or progress over a short period of time.2,6
Common symptoms include:1,2,6
Some symptoms, such as difficulty with coordination, numbness or tingling, weakness in specific areas, or double vision, overlap with those seen in multiple sclerosis (MS). However, BCS lesions can sometimes cause symptoms more like those caused by brain tumors. In rare cases, symptoms may resemble those of a stroke, or the condition may cause no noticeable symptoms at all.6,8
In children, BCS can lead to behavioral changes or difficulties with school performance.4 In some people, vision problems, dizziness, or involvement of the spinal cord and balance center of the brain (cerebellum) may occur.2
Tests of the cerebrospinal fluid (CSF) often show signs of inflammation, and in some people, specific immune-related proteins called oligoclonal bands may be present.6
The exact cause of BCS is still unknown. However, medical experts think it is autoimmune in nature, meaning the body’s own defense system mistakenly attacks healthy brain tissue.2 One theory is that minor injuries at the edges of brain lesions trigger the brain to try to protect itself. This may result in alternating layers of damage and repair, leading to the ring-shaped patterns seen on imaging.2
When scientists examined affected brain tissue, they found signs of inflammation, with immune cells like T cells, macrophages and B cells (types of white blood cells) involved in the damage. Some cases may also involve a lack of blood flow or oxygen to parts of the brain, contributing to the ring-shaped injury pattern.2
BCS is very rare, and because of its complexity, exact numbers are hard to determine. In the United States, nearly 1 million people live with MS; only a very small number have BCS.⁵ BCS can affect both children and adults; the average age of diagnosis is around 36, but BCS has been reported in younger and older people.1,3
In children, MS accounts for less than 5% of all cases, and BCS is even more uncommon. However, some children have been diagnosed with large brain lesions caused by BCS which can be mistaken for brain tumors.³
Diagnosis of BCS can be difficult because its symptoms and brain imaging can look like other diseases. The most important tool for diagnosis is magnetic resonance imaging (MRI), which provides detailed pictures of the brain.
In BCS, MRI scans often show concentric ring patterns which are alternating circles of normal and damaged brain tissue.2,3 These ring patterns are what help doctors distinguish BCS from other conditions. A special test called MR spectroscopy can also be used. It analyzes the chemical makeup of brain lesions to determine whether the problem is due to inflammation (as in BCS) or something else like a brain tumor.3,4 There is no strict cut-off number of rings to diagnose a BCS lesion. However, the consensus requires at least two or more concentric demyelinated lesions to call it a “Balo-like lesion”.7
Advanced imaging techniques play a crucial role in accurately diagnosing BCS. One such method, MRI tractography, allows doctors to visualize the brain’s white matter in detail and precisely identify the size and location of lesions. Other tools, such as FDG-PET scans and magnetic resonance spectroscopy, provide additional insights by revealing chemical changes in the brain similar to those seen in multiple sclerosis.11
In more severe cases of BCS, imaging may show large, layered lesions that resemble moon craters. This distinctive “onion bulb” pattern, caused by alternating layers of damaged and preserved nerve fibers, is a hallmark of the disease and helps distinguish it from other conditions.11
Doctors consider several possibilities when diagnosing BCS, including other diseases like brain tumors, abscesses and certain infections. However, these typically do not show the unique ring-like pattern seen in BCS, making early imaging especially helpful for an accurate diagnosis. Additionally, BCS tends to cause sudden and severe neurological symptoms, which sets it apart from other conditions that usually progress more gradually.9,11
Treatment
There is currently no standard treatment plan for BCS, mostly because it’s extremely rare and not well studied. Treatment often involves a team of specialists, including neurologists, radiologists and psychologists, to support both medical and emotional needs.3
Treatment usually starts with corticosteroids (like methylprednisolone) which are medications that reduce swelling in the brain and often lead to fast improvement in symptoms and MRI findings.5 In addition, they calm down the body’s immune system, which may be attacking healthy tissue by mistake.
Other treatments may include:2-7,9,11
In children, treatment must be customized carefully. Children may react differently than adults, and many medications are not FDA-approved for pediatric MS.3
Doctors may also give medications to help manage specific symptoms like pain, muscle weakness, or movement problems, depending on what the patient is experiencing.
Encouragingly, while BCS was once thought to be a rapidly fatal condition, more recent reports show that some people experience long-term remission, recovery, or even minimal symptoms, especially with early diagnosis and proper treatment.2,3,7,9,11
Information on current clinical trials is posted on the Internet at https://clinicaltrials.gov/
All studies receiving U.S. Government funding, and some supported by private industry, are posted on this government web site.
For information about clinical trials being conducted at the NIH Clinical Center in Bethesda, MD, contact the NIH Patient Recruitment Office:
Tollfree: (800) 411-1222
TTY: (866) 411-1010
Email: [email protected]
Some current clinical trials also are posted on the following page on the NORD website: https://rarediseases.org/living-with-a-rare-disease/find-clinical-trials/
For information about clinical trials sponsored by private sources, contact: http://www.centerwatch.com/
For information about clinical trials conducted in Europe, contact: https://www.clinicaltrialsregister.eu/
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The Genetic and Rare Diseases Information Center (GARD) has information and resources for patients, caregivers, and families that may be helpful before and after diagnosis of this condition. GARD is a program of the National Center for Advancing Translational Sciences (NCATS), part of the National Institutes of Health (NIH).
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