Characteristics of Moyamoya Syndrome in Pediatric Patients With Neurofibromatosis Type 1.

BACKGROUND: Moyamoya syndrome (MMS) is a progressive cerebral arteriopathy with increased incidence in children with neurofibromatosis type 1 (NF1). Despite the potential for significant neurological morbidity including stroke, little is known about the natural history, and no guidelines exist for screening and management of NF1-associated MMS. METHODS: We identified 152 literature cases of children aged ≤18 years with NF1-associated MMS. A meta-analysis was performed evaluating clinical and neuroimaging findings and patient outcomes. Data from 19 patients with NF1-associated MMS from our center treated from January 1995 to July 2020 were abstracted via chart review and similarly analyzed for clinical and neuroimaging features. RESULTS: Meta-analysis of literature cases showed a median age of MMS diagnosis of 6 years (interquartile range 3 to 10.8 years). Optic pathway gliomas were more common in patients with MMS (42%) compared with historical prevalence. Stroke or transient ischemic attack (TIA) was present at diagnosis in 46%. TIA and stroke were more common in patients with bilateral versus unilateral MMS (62% vs 34%, P = 0.001) and in children aged <4 years versus those aged ≥4 years (61% vs 40%, P = 0.02). Compared with the literature cases, our cohort was more frequently asymptomatic (42% vs 25%) and less likely to present with TIA or stroke (32% vs 46%) at diagnosis. CONCLUSIONS: These data suggest there is an aggressive form of MMS in children with NF1 <4 years of age. Therefore, early screening should be considered to facilitate early detection and treatment of cerebral arteriopathy.