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

Paramagnetic-rim lesions are a novel diagnostic marker in multiple sclerosis (MS) and are associated with poor prognosis due to their link with chronic inflammation and disease progression. Analyzing 46 postmortem MS cases, researchers found no iron rims in 67 white matter and 85 grey matter spinal cord lesions, despite most being active. In contrast, iron rims appeared in 20.9% of cortical and 80% of subcortical brain lesions, especially in deeper myelin-rich cortical layers. These findings highlight the regional variability of iron accumulation and have important implications for interpreting iron-rims in MS diagnosis, monitoring, and prognostication. ANN NEUROL 2026;99:730-736.