Topographical Variation of Iron-Rimmed Lesions in the Multiple Sclerosis Brain and Spinal Cord: A Neuropathological...

Area of Science:

• Neuroimmunology
• Neurodegeneration
• Biomarker Discovery

Background:

• Paramagnetic-rim lesions are emerging diagnostic markers in multiple sclerosis (MS).
• These lesions are linked to chronic inflammation and disease progression, indicating poor prognosis.
• Understanding their distribution is crucial for MS management.

Purpose of the Study:

• To investigate the presence and distribution of paramagnetic-rim lesions in the spinal cord and brain of postmortem MS cases.
• To determine the association between iron rims and lesion activity, location, and myelination status.

Main Methods:

• Analysis of 46 postmortem multiple sclerosis (MS) cases.
• Histopathological examination of white matter and grey matter lesions in the spinal cord and brain.
• Assessment of iron rim presence in cortical and subcortical lesions, correlating with myelin content.

Main Results:

• No iron rims were detected in spinal cord white matter (67 lesions) or grey matter (85 lesions), despite lesion activity.
• Iron rims were observed in 20.9% of cortical and 80% of subcortical brain lesions.
• Iron accumulation was more prevalent in deeper, myelin-rich cortical layers.

Conclusions:

• Significant regional variability exists in iron accumulation within MS lesions.
• The absence of iron rims in spinal cord lesions challenges their universal diagnostic utility.
• Findings necessitate a nuanced interpretation of iron-rim lesions for MS diagnosis, monitoring, and prognostication.