This single-center retrospective cohort study investigates small vessel predominant primary CNS vasculitis (sv-PCNSV), a rare autoimmune disorder affecting brain and spinal cord blood vessels. Researchers analyzed data from 26 patients with biopsy-proven sv-PCNSV to understand their clinical features and the effectiveness of different treatments. The study compared an early intensive treatment (EIT) group receiving cyclophosphamide within three months of immunosuppression with an escalation treatment (ESC) group given initial glucocorticoids. Findings indicate that EIT was associated with a significantly shorter time to remission (5 months vs. 19 months), highlighting the importance of timely and aggressive treatment for this condition. While all patients in the EIT group achieved remission, 78.6% did in the ESC group, suggesting a benefit from early cyclophosphamide.