Abstract T P366: Moyamoya Following Treatment of Intracranial Tumors

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Introduction: We present our experience with the management of patients initially diagnosed with intracranial tumor who subsequently developed moyamoya following tumor treatment. Hypothesis: We hypothesized that moyamoya associated with brain tumors would demonstrate similar radiographic findings and response to surgery as idiopathic moyamoya and that radiotherapy would increase stroke risk. Methods: Single institution series reviewing all moyamoya cases from 1985-2014 to identify those initially diagnosed with intracranial tumor who subsequently developed moyamoya. Results: 26 patients (12M/14F) diagnosed with 27 intracranial tumors later developed moyamoya. Average age at tumor diagnosis was 4.6yr (range 0.5 - 14.7) and 9.8yr at moyamoya diagnosis (range 5.0 - 19.7). 21 tumors had radiotherapy, 16 chemotherapy, and 14 surgical resection, 2 of whom underwent surgery alone without adjuvant therapy. Radiotherapy patients had moyamoya diagnosed 3.9yr after radiation (range 0.2 - 13.8). All patients (100%) presenting with stroke had radiation. Initial moyamoya symptoms included TIA (58%), stroke (42%), and seizure (19%); moyamoya was incidental discovery in 23%. 13 patients (50%) had stroke on imaging; their average Suzuki grade was 3. 45 pial synangiosis were performed, 19 with bilateral surgery. Postoperative complications included stroke in 2 patients (4.4% per operation). 2 patients had a stroke during follow up unrelated to moyamoya but rather from small vessel disease in the brain stem resulting from radiotherapy. Postoperative arteriograms demonstrated Matsushima grade A/B collaterals in 75% of patients studied (n=24 hemispheres). Eight patients required further treatment for tumor recurrence or progression. Conclusions: In conclusion, pediatric brain tumor patients develop moyamoya arteriopathy clinically and radiographically similar to idiopathic moyamoya. Radiotherapy is associated with increased incidence of radiographic stroke in this cohort. Secondary injury from radiation may occur in the posterior fossa, but ischemia from moyamoya in the cerebral hemispheres can be corrected with revascularization conferring durable protection from stroke.