Oro-mandibular dystonia in pediatric moyamoya disease: Two cases report.

Background: In this report, we describe rare two pediatric cases that developed oro-mandibular dystonia due to moyamoya disease.

Case Description: A 7-year-old boy presented with oro-mandibular dystonia and transient weakness of the left extremities, and was diagnosed as moyamoya disease. Another 7-year-old boy developed oro-mandibular dystonia alone and was diagnosed as moyamoya disease. In both, cerebral blood flow (CBF) was markedly decreased in the involved hemispheres, including the basal ganglia and cerebral cortex. They successfully underwent combined bypass surgery and experienced no further attacks of oromandibular dystonia during follow-up periods. CBF almost normalized through surgical collaterals through direct and indirect bypass.

Conclusion: When treating patients with oro-mandibular dystonia, moyamoya disease should be listed as one of the differential diseases. The underlying mechanism of oro-mandibular dystonia in moyamoya disease is still unclear, but persistent cerebral ischemia in the basal ganglia and/or parietal lobe may play a key role to induce this rare symptom.