Prenatal ultrasound detection of bilateral focal polymicrogyria

Objectives: Prenatal diagnosis by ultrasound of fetal polymicrogyria has been reported only once. Methods: We describe an additional case of polymicrogyria in a fetus from a monozygotic twin pair, probably the consequence of twin-to-twin transfusion syndrome. Results: On ultrasound, there were bilateral cortical hyperechogenic spots, and prenatal magnetic resonance imaging demonstrated the typical features of bilateral focal polymicrogyria. Conclusion: Polymicrogyria can be considered in the differential diagnosis of hyperechogenic brain lesions on fetal ultrasound. We also confirm the risk of brain damage in monochorionic twins pregnancies and the likely hypoxic-ischemic etiology of polymicrogyria.