Balo concentric sclerosis
|Balo concentric sclerosis|
|Classification and external resources|
Typical aspects of Baló's concentric sclerosis. (a) Original case of Baló; several anastomoses are located in the lower half of the lesion. (b) Lesion centered by a veinule showing ring fragmentation in a constrained area. (c) Lesion. (d) Progress of the pathologic process from a center located in a constrained area, showing formation of bands. Loyez staining (myelin in black, destroyed areas in white); scale bars: 1 cm.
Balo concentric sclerosis is one of the borderline forms of multiple sclerosis.
Balo concentric sclerosis is a demyelinating disease similar to standard multiple sclerosis, but with the particularity that the demyelinated tissues form concentric layers. Scientists used to believe that the prognosis was similar to Marburg multiple sclerosis, but now they know that patients can survive, or even have spontaneous remission and asymptomatic cases.
It is also common that the clinical course is primary progressive, but a relapsing-remitting course has been reported. It seems that the course gets better with prednisone therapy, although evidence of this is anecdotal and such conclusions are difficult to accept given that there are cases where patients spontaneously recover whether the patient was on steroid therapy or not.
According with Dr. Lucchinetti investigations, in Balo's concentric sclerosis, the rings may be caused by a physiological hypoxia (similar to that caused by some toxins or viruses) in the lesion, which is in turn countered by expression of stress proteins at the border. This expression and counter-expression forms rings of preserved tissue within the lesion and rings of demyelinated tissue just beyond where the previous attack had induced the protective stress proteins. Hence, subsequent attacks form concentric rings.
Ultimately, this expanding lesion causes the progressive picture typically seen. However, in some patients, the pathology underlying the disease appears to burn out and hence the disease may halt, hence the patients who spontaneously recover. The mechanisms triggering attacks and recovery remain uncertain.
The features of the MRI and the characteristics of the lesion can be correlated when a biopsy has been taken, providing a way to standarize the future MRI diagnosis
Recently, a mathematical model for concentric sclerosis has been proposed. Authors review the previous pathogenic theories, discuss the link between concentric sclerosis and Liesegang's periodic precipitation phenomenon and propose a new mechanism based on self-organization.
Balo concentric sclerosis in children has been reported to behave different from adults
Lesions under autopsy and biopsy
A report comparing 1H-magnetic resonance spectroscopy, magnetization transfer and diffusion tensor imaging with histopathology in a patient with Balo's concentric sclerosis, found that inflammation was traced by fractional anisotropy and increased lactate. In contrast, magnetization transfer ratio and the diffusion coefficient show a loss of tissue in the rings of the lesion.
Lesions under MRI
Balo concentric sclerosis lesions can be distinguished from normal lesions on RMI showing alternative hypotense and hypertense layers
- Karaarslan E, Altintas A, Senol U, et al. (August 2001). "Baló's concentric sclerosis: clinical and radiologic features of five cases". AJNR Am J Neuroradiol 22 (7): 1362–7. PMID 11498428.
- Moore GR, Berry K, Oger JJ, Prout AJ, Graeb DA, Nugent RA (December 2001). "Baló's concentric sclerosis: surviving normal myelin in a patient with a relapsing-remitting dinical course". Mult. Scler. 7 (6): 375–82. doi:10.1177/135245850100700606. PMID 11795459.
- Garbern J, Spence AM, Alvord EC (December 1986). "Balo's concentric demyelination diagnosed premortem". Neurology 36 (12): 1610–4. doi:10.1212/WNL.36.12.1610. PMID 3785678.
- (Article in Spanish)
- Genetic susceptibility in MS – Steve Hauser. Rare Neuroimmunologic Disorders Symposium 
- Darke, Bahador, Miller, Litofsky, Ahsan. Baló's concentric sclerosis: imaging findings and pathological correlation, J Radiol Case Rep. 2013 Jun 1;7(6):1-8. doi: 10.3941/jrcr.v7i6.1251. PMID 24421937
- Khonsari RH, Calvez V (2007). Monk, Nick, ed. "The Origins of Concentric Demyelination: Self-Organization in the Human Brain". PLoS ONE 2 (1): e150. doi:10.1371/journal.pone.0000150. PMC 1764710. PMID 17225855.
- Linnoila J, Chitnis T. Balo Concentric Sclerosis in Children: A Case Series, J Child Neurol. 2014 Jan 14. PMID 24423690
- S. Lindquist, Histopathology and serial, multimodal magnetic resonance imaging in a multiple sclerosis variant, Mult Scler May 2007 vol. 13 no. 4 471-482
- IANNUCCI et al. Vanishing Balò-like lesions in multiple sclerosis, J Neurol Neurosurg Psychiatry 2000;69:399–400
- Article at mult-sclerosis.org
Khonsari RH, Calvez V (September 2007). "Concentric demyelination by self-organization: a new hypothesis for Baló's sclerosis". Nat Clin Pract Neurol 3 (9): E1. doi:10.1038/ncpneuro0619. PMID 17805242.