Efficacy of Direct Revascularization Surgery for Hemorrhagic Moyamoya Syndrome As a Late Complication of Cranial Irradiation for Childhood Craniopharyngioma

Moyamoya syndrome (MMS) is an uncommon late complication after cranial irradiation. Its hemorrhagic presentation from the associated pseudo-aneurysm is extremely rare, and the optimal management strategy is undetermined. We herein report a 36-year-old man who developed intraventricular hemorrhage from a pseudo-aneurysm at the extended left anterior choroidal artery as an abnormal collateral of MMS 30 years after surgical removal and cranial irradiation for childhood craniopharyngioma. Catheter angiography confirmed the diagnosis of MMS, and multiple pseudo-aneurysms were evident at the ipsilateral abnormal choroidal collateral, one of which was considered to be a source of bleeding. The patient underwent left superficial temporal artery (STA)-middle cerebral artery (MCA) anastomosis with indirect pial synangiosis based on the observation that the development of choroidal collateral may be associated with a high rebleeding risk in hemorrhagic moyamoya disease. The patient was discharged without neurological deficit, and postoperative magnetic resonance angiography confirmed the STA-MCA bypass to be patent. Catheter angiography 1 year after revascularization surgery revealed the complete disappearance of the pseudoaneurysms with the apparently patent STA-MCA bypass. The patient did not exhibit any cerebrovascular events during the follow-up period of 16 months. In conclusion, hemorrhagic MMS with choroidal collateral as a dangerous anastomosis was effectively managed by STA-MCA anastomosis. Although long-term follow-up is necessary to evaluate our strategy, the favorable disappearance of pseudoaneurysms after revascularization surgery in the present case strongly suggests that STA-MCA anastomosis has a potential role for preventing rebleeding in MMS after cranial irradiation.