* Department of Gynecology, Félix Guyon’Hospital ** Sonographer, Moufia’street *** Department of Obstetric, Hôpital intercommunal de Saint Benoît, Ile de la réunion, France.

Case report: This is a 25-year-old primigravida without any relevant past obstetrical history. The first scan was normal. The nuchal translucency (1 mm) and the triple test (1/1200) were also normal. The level of maternal-fetoprotein was 1,5 MoM. At 22 weeks a scan revealed an Arnold Chiari malformation with a sacral spinal defect (S2S3). An amniocentesis was performed (normal karyotype). At 22 weeks a sacral anomaly was seen suggestive of a myelomeningocele. The inferior limbs had normal movements. The bladder appeared normal. The findings with the 3D scans were identical. The head was abnormal with a "lemon-shape" sign. At 23 weeks a repeat scan was performed. There was an initial hydrocephaly (atrial dilatation: 11 and 12 mm) and the Arnold Chiari syndrome was confirmed. At 24 weeks, hydrocephaly had increased (atrial dilatation = 12 mm). The third ventricle was dilated.

The parents decided to interrupt the pregnancy. They refused the anatomic-pathological examination. External analysis confirmed the sacral defect.

Note the sacral spine defect

Dilatation of the lateral ventricles and third ventricle

Post-natal view

Note the spine defect