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

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.