Abstract
Polyhydramnios is a non-specific prenatal finding associated with several fetal anomalies, most notably gastrointestinal obstructions, such as esophageal atresia (EA). However, its etiology may extend beyond gastrointestinal causes to include central nervous system (CNS) abnormalities. We report the case of a neonate initially suspected in utero to have EA based on polyhydramnios and a small fetal gastric bubble, but postnatally diagnosed with classical lissencephaly associated with Miller-Dieker syndrome. A 32-year-old primigravida was referred to our center at 28 weeks of gestation on account of suspected fetal EA with polyhydramnios and a small gastric bubble on prenatal ultrasonography (US). No other anomaly was identified, and she was admitted for management at 30 4/7 weeks of gestation. The patient was delivered at 36 3/7 weeks of gestation via emergency cesarean section due to premature rupture of membranes and arrest of vaginal labor. The neonate showed no sign of EA, and that diagnosis was excluded based on successful passage of an orogastric tube and normal abdominal radiography. Mild dysmorphic features, such as micrognathia and hypertelorism, were noted. As the etiology of polyhydramnios remained unclear, neuroimaging was performed. Cranial US findings were unremarkable; however, head magnetic resonance imaging (MRI) on day seven of life revealed a thickened cortex lacking normal sulcation, which is consistent with classical lissencephaly. Chromosomal microarray analysis revealed a deletion on 17p13.3, confirming Miller-Dieker syndrome. The patient was discharged on day 35 after an uneventful neonatal period; however, epileptic spasms and developmental delay were noticed from the age of six months. This case highlights the diagnostic challenge of differentiating between gastrointestinal and neurological causes of polyhydramnios. Although EA is a common differential diagnosis in such cases, the potential for CNS malformations mimicking gastrointestinal pathologies must be considered. Routine fetal ultrasound alone may fail to detect subtle cerebral abnormalities such as lissencephaly, especially in the absence of ventriculomegaly or other signs. Fetal MRI, which has superior soft tissue resolution, should be considered when the etiology of polyhydramnios is uncertain, even if there is no overt CNS anomaly. This case highlights the importance of prompt neuroimaging, including fetal MRI, which may facilitate diagnosis and counseling of families, and optimize postnatal care.