Case Report: Unilateral relapsing primary central nervous system vasculitis—expanding the phenotype

Compared with typical PCNSV, this rare unilateral, relapsing subtype has a younger age of onset, lower prevalence of angiographic abnormalities, and frequent relapses. Our patients had persisting lesion enhancement despite anti-CD20 mAb monotherapy and demonstrated hemiatrophy within the first year, indicating high inflammatory activity and a requirement for additional immunosuppression. This case series additionally highlights the overlapping clinical and radiological features of PCNSV and CNS demyelination, which may contribute to diagnostic delay.