LAUSR

ABSTRACT Introduction: Blake's pouch cyst (BPC) represents an abnormal development of the posterior membranous area of the fetal brain. Material and Methods: Two- and three-dimensional ultrasound with Cristal and Realistic Vue were used to characterized the early prenatal diagnosis. Results: At 9 weeks and 5 days a ballooning in the posterior fossa and resulting in an enlarged intracranial translucency (IT) was detected by 3D ultrasound using Cristal Vue in “inversion” mode and Cristal plus Realistic Vue. In addition, an increased nuchal translucency (7 mm) due to septated cystic hygroma (SCHy) was an associated finding. Hydrops fetalis ensued and a chorionic villus sampling at 12 weeks revealed a 45,X monosomy with persisting BPC. Follow up scan were planned fortnightly. A spontaneous miscarriage occurred at 16 weeks. Conclusion: Three-dimensional ultrasound with Cristal and Realistic Vue aided the prenatal diagnosis of BPC in the first trimester.