Baló concentric sclerosis

Last revised by Rohit Sharma on 20 Feb 2024

Baló concentric sclerosis is a rare and severe monophasic demyelinating disease, considered a subtype of multiple sclerosis, appearing as a rounded lesion with alternating layers of high and low signal intensity on MRI, giving it a characteristic 'bullseye' or 'onion bulb' appearance 1,9.

It is a rare disorder most commonly found among people of Han Chinese and Filipino descent, although multiple sclerosis in these populations is less common than in Caucasians 10.

The presentation can be similar to other forms of multiple sclerosis, although it is usually monophasic, most closely resembling acute Marburg type multiple sclerosis, with rapid progression and sometimes fulminant course 4,8,9.

Concentric layers of alternating demyelination and preserved myelin are seen, resulting in the characteristic imaging appearance, although the exact mechanism remains unclear 8.

The characteristic feature is the development of alternating bands of demyelinated and myelinated white matter, which is seen as concentric rings or irregular stripes of high or low signal depending on the sequence, giving it a characteristic 'bullseye' or 'onion bulb' appearance 9:

  • T1: irregular concentric areas of iso and low signal

  • T2: irregular concentric areas alternating iso/hypointense and hyperintense signal 4,9

  • T1 C+ (Gd): typically a peripheral ring of enhancement in the area of active demyelination 9

  • DWI: some restricted diffusion in the outer ring 7

As with other forms of multiple sclerosis, corticosteroid has been used. The condition tends to have a rapidly progressive course but not necessarily fatal 1,4,6,8.

It is named after József Baló (1895–1979), Hungarian neuropathologist who first published the unusual case and subsequent death of a young law student who presented with fulminantly deteriorating, focal neurological symptoms in 1928 11. "Leuko-encephalitis periaxialis concentrica" was the term he proposed to be used to the concentric focus of gray and white layers in the white matter he found during autopsy 2,11.

Imaging differential considerations include:

ADVERTISEMENT: Supporters see fewer/no ads

Cases and figures

  • Figure 1: 'bullseye' or 'onion bulb' appearance
    Drag here to reorder.
  • Case 1: possible Balo concentric sclerosis
    Drag here to reorder.
  • Case 2: possible Balo concentric sclerosis
    Drag here to reorder.
  • Case 3
    Drag here to reorder.
  • Case 4
    Drag here to reorder.
  • Updating… Please wait.

     Unable to process the form. Check for errors and try again.

     Thank you for updating your details.