Primary central nervous system vasculitis mimicking brain tumor: Comprehensive analysis of 13 cases from a single institutional cohort of 191 cases

Abstract Objective To describe the clinical, laboratory, and imaging features and course of patients with primary central nervous system vasculitis (PCNSV) presenting with an intracranial tumor-like mass (TLM). Methods We retrospectively studied a cohort of 191 consecutive patients with PCNSV seen at the Mayo Clinic, Rochester, MN over a 35-year period (1982–2017). 13/191 patients presented with a TLM. We compared the findings in these 13 patients with those from the 178 without this presentation. Results In 13 of 191 (6.8%) patients with TLM the diagnosis of PCNSV was established by cerebral biopsy. Granulomatous vasculitis was found in 11/13 patients, accompanied by vascular deposits of β-amyloid peptide in 7. Compared to the 178 patients without TLM, the patients with TLM were more likely to be male (p = 0.04), and less likely to have a transient ischemic attack (p = 0.023), bilateral cerebral infarcts (p = 0.018), or vasculitic lesions on angiography (p = 0.045). They were more likely to have seizures (p = 0.022), gadolinium-enhanced lesions (p = 0.007), and amyloid angiopathy (p = 0.046). All 13 patients responded to therapy and 8/13 (61.5%) had a Rankin disability score of 0 at last visit. Overall, high disability scores (Rankin scores 4–6) at last follow-up were associated with increasing age (odds ratio, OR, 1.49) and cerebral infarction (OR, 3.47), but were less likely in patients with gadolinium-enhanced lesions (OR, 0.36) and amyloid angiopathy (OR, 0.21). Conclusion In PCNSV a TLM at presentation represents a definable subgroup of patients with a favourable treatment response.