Moyamoya Syndrome Associated with Late-onset Idiopathic Aqueduct Stenosis Successfully Treated with Endoscopic Third Ventriculostomy

Abstract

Moyamoya disease (MMD) is a rare idiopathic cerebrovascular disorder that causes transient ischemic attack (TIA) and ischemic stroke in the pediatric population. Herein, we report an extremely rare case of Moyamoya syndrome (MMS) and late-onset idiopathic aqueduct stenosis, a unique form of non- communicating hydrocephalus. A 17-year-old female presented with an intractable headache and oc- casional faintness. Pertinent medical history included a fourth ventricle epidermoid cyst without any evidence of aqueduct stenosis, which was surgically removed when she was two years of age. The pa- tient subsequently experienced a TIA and was diagnosed with MMD at 14 years of age. Under the de- finitive diagnosis of MMS associated with a brain tumor, the patient underwent surgical revasculariza- tion of the symptomatic right hemisphere without complications. Although the ischemic symptoms re- solved postoperatively, a medically intractable headache with occasional faintness persisted. Serial magnetic resonance imaging ultimately revealed newly developed non-communicating hydrocephalus due to acquired aqueduct stenosis at the age of 17. After careful exclusion of the development of either or both a periventricular anastomosis and vault moyamoya vessels along the surgical route us- ing cerebral angiography, we performed an endoscopic third ventriculostomy (ETV) via the right ante- rior horn without complications. A complete resolution of her chronic headache with the shrinkage of the third ventriculomegaly was observed postoperatively. In cases of MMS associated with sympto- matic aqueduct stenosis, transdural collaterals on the cranial vault and periventricular collaterals should be meticulously evaluated preoperatively using cerebral angiography to safely perform an ETV.