IN UTERO IDENTIFICATION OF COMMISSURAL ANOMALIES – THE EXPERIENCE OF THE FETAL NEUROLOGY MULTIDISCIPLINARY CLINIC

Objectives: To describe the imaging and clinical findings in a cohort of fetuses with commissural anomalies (CA).

Methods: We retrospectively reviewed, the files of all fetuses diagnosed as affected by any type of CA during the period of 1989–2005.

Results: 55 fetuses were identified. The mean gestational age at the time of US diagnosis was 26.8 weeks. Complete agenesis of the corpus callosum (ACC) was present in 25, dysgenesis of the CC in 20, thickening of the CC in 3, lipoma of the CC in 3, vellum interpositum cysts in 2, one with ACC but normal anterior commissure and one with the middle interhemispheric variant of holoprosencephaly. Commissural anomalies were isolated in 21 patients; associated anomalies were found in the remaining 34. Colpocephaly was present in only 24 fetuses. Associated anomalies were found in 11/25 fetuses with complete ACC and in fetuses with other forms of CA. MR imaging was performed starting form 2000 in 15 patients. Thirty-seven patients opted for termination of pregnancy, one fetus died in utero. 16 were delivered and one pregnancy is still ongoing. One child died close to delivery. 2 were lost to follow-up. Nine children have normal development (mean follow up 25.2 months). One has severe psychomotor retardation, two mild developmental delay and one optic nerve hypoplasia.

Conclusion: Commissural anomalies can be diagnosed in utero by US. The increasing knowledge of brain anatomy gained in the last years seems to be an important factor in the increased diagnostic yield. Following prenatal counseling, 67% of our population opted for termination of pregnancy; this number is even higher (74%) if we exclude 5 fetuses with relatively benign findings (lipoma and cavum interpositum cyst). On the other hand, patients with the US and MRI diagnosis of isolated ACC or CC lipomas seem to have a good prognosis (6/6).