P15.03: Prenatal diagnosis and outcome of partial agenesis and hypoplasia of the corpus callosum

To assess the feasibility of prenatal diagnosis and the outcome of partial agenesis (PACC) and hypoplasia of corpus callosum (HCC). PACC/HCC were suspected on fetal multiplanar neurosonography when the corpus callosum appeared caudally shorter and thinner respectively. Follow-up was obtained in all cases. Between 1990–2003, 8 cases of PACC and 3 cases of HCC were identified at a median gestational age of 22 weeks (21–33) (see table). The cavum septi pellucidum was present in 9 cases, in 7 there was mild to severe ventriculomegaly, usually in association with ‘teardrop’ lateral ventricles, and 4 had associated cerebral anomalies (Dandy-Walker complex, emimegalencephaly, microcephaly). Magnetic resonance (MR) was performed in 4/11 cases without adding significant information. Five fetuses were terminated, 7 had multiple anomalies, and 3 are developing normally. PACC can be reliably diagnosed since midgestation. However, multiplanar neurosonography is required. On standard axial planes sonographic findings are similar to complete agenesis but more subtle. In particular the cavum septi pellucidum is usually present. MR did not offer significant advantage over multiplanar neurosonography. HCC was an incidental finding usually in fetuses with multiple anomalies. The outcome of PACC/HCC is similar to complete agenesis of the corpus callosum.