P38.02: Aqueductal stenosis caused by fetal intracranial hemorrhage and leptomeningeal infection: two unusual cases of third trimester ventriculomegaly

We report two unusual cases of ventriculomegaly detected during the third trimester of pregnancy, in which the initial evaluation was performed by ultrasonography. Fetal MRI was used as a supplemental diagnostic imaging modality. A 27-year-old, primigravid woman was referred to our maternal fetal medicine unit with the diagnosis of hydrocephalus at 32 weeks of gestation. Her prenatal follow-up was uneventful. We detected dilatation of third, and both lateral ventricles during ultrasound examination. A mass appearance was observed at the level of the anterior horn of right lateral ventricles. Fetal MRI was requested and confirmed aqueductal stenosis and enlarged lateral, third ventricles and right germinal matrix hemorrhage with subsequent development of hydrocephalus. The second case was a 22-year-old primigravid woman referred to us for severe hydrocephaly at 33 weeks of gestation. Polyhydramniosis was noticed during ultrasound examination. Fetal ultrasound examination at 33 weeks of gestation revealed colpocephaly, irregular borders of dilated lateral ventricles and also dilatation of third and fourth ventricles. Differential diagnosis for fetal ultrasound findings were agenesis of corpus callosum, stenosis of aqueductal canal and perinatal TORCH infections. Fetal cranial evaluation with MRI found colpocephaly, periventricular leukomalacia around the anterior horn of the enlarged lateral ventricles and the edema near the corpus callosum. We detected high density material inside the ventricles at the level of anterior horn. Parents in both cases were provided with prenatal genetic consultation. First case was delivered in another institution. The neonate died soon after birth. The second patient delivered at Acibadem Hospital following application of fetocide and induction of labor. Autopsy analysis was consistent with bilateral hydrocephaly and revealed basal lymphocytic leptomeningitis and lymphocytic plexit at choroid plexus of fourth ventricle.