to problems in the water channel of the astrocytes It presents three clinical subtypes: Monophasic, relapsing-remitting and primary rapidly progressive. Cerebrospinal fluid (CSF) is either normal or shows mild mononuclear inflammatory reaction. CSF-restricted oligoclonal bands are present only in a minority of cases Other models 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. Clinical courses The clinical course is primarily 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. Baló lesions can disappear over time, but it has also been reported that the disease can convert to RRMS The clinical course of Balo-like lesions also depends to the context in which they appear. Balo-like lesions have been reported in aquaporin-4 seropositive and seronegative NMOSD, and also in children, as part of an ADEM-like presentation Diagnosis Lesions under MRI are distinctive due to their natural concentric shape. Under a lumbar puncture CSF test, with Baló's concentric sclerosis, as well as patients with pattern III lesions, were recently shown to be mostly negative for CSF-restricted oligoclonal bands. Also pattern III patients tend to be negative under the MRZ-reaction (measles, rubeola and zoster viruses) Paediatric cases Baló's concentric sclerosis in children has been reported to behave different from adults Lesions in autopsy and biopsy A report comparing 1H-magnetic resonance spectroscopy, magnetization transfer and diffusion tensor imaging with histopathology in a patient with Baló'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 The features of the MRI and the characteristics of the lesion can be correlated when a biopsy has been taken, providing a way to standardize the future MRI diagnosis Baló's concentric sclerosis lesions can be distinguished from normal lesions on MRI showing alternating hypointense and hyperintense layers Baló's concentric lesions can be viewed using the myelin water imaging techniques. This is a special MRI sequence that shows the myelin's percentage of water content. Pattern III lesions, including Baló