Long-term clinical, MRI, and cognitive follow-up in a large cohort of pathologically confirmed, predominantly tumefactive multiple sclerosis.

Despite early aggressive course in pathologically confirmed MS, its long-term course was comparable to typical MS in our study. Cognitive impairment in this group seemed to correlate strongest to index lesion severity and total lesion volume. It remains to be established how the aggressive nature of the lesion, biopsy, and treatment affect clinical/cognitive outcomes.