Moyamoya disease mimicking primary central nervous system vasculitis: A case report

Abstract

Rationale: Both Moyamoya disease (MMD) and primary central nervous system vasculitis (PCNSV) cause cerebrovascular stenosis resulting in similar ischemic neurological events, although therapeutic approaches are distinct from each other. High-resonance vascular wall imaging (HRVWI) with contrast-enhanced magnetic resonance imaging (MRI) is believed to be useful to differentiate PCNSV from MMD by detecting enhancement of cerebral vascular walls. However, recent studies have reported that the vascular walls of major arteries and superficial cerebral arteries are also enhanced by HRVWI in some MMD cases. Patient concerns: A 40-year-old Chinese woman admitted to our hospital with transient weakness of the right hand for a week. A cerebral infarction of the left frontal lobe was detected by diffusion-weighted brain MRI. Magnetic resonance angiography demonstrated severe stenosis of the left middle cerebral artery (MCA) and extensive vascular narrowing. Magnetic resonance angiography incidentally taken 3 years before admission showed only a mild stenosis at the proximal portion of right MCA with intact left internal carotid artery (ICA) and MCA. Moreover, on HRVWI with contrast-enhanced MRI after admission, the wall of ICA was strongly enhanced, and the superficial cerebral arteries were also highly enhanced, which initially suggested PCNSV. Despite these findings, reticular blood vessels were confirmed by digital subtraction angiography, and p.R4810K polymorphism in the ring finger protein 213 gene was detected. Diagnosis: Based on these result, the patient was diagnosed with MMD. Interventions: Bypass surgery was performed. Outcomes: Ischemic events have never been experienced since surgery. Lessons: Our MMD case demonstrated marked asymmetrical progression of cerebral artery stenosis, and enhanced vascular walls of ICA and superficial cerebral arteries by HRVWI, which made differential diagnosis from PCNSV difficult. Genetic analysis of SNP in the ring finger protein 213 gene should be performed to rule out MMD to avoid misdiagnosis of PCNSV particularly in Asian population.