EP05.51: Fetal Blake's pouch cyst: ultrasound features, associations and outcome

To evaluate the prevalence and significance of fetal Blake's pouch cyst (BPC) detected on screening ultrasound (US) scans. Retrospective study, carried out over 3 years period. Fetuses with posterior fossa anomalies and a final diagnosis of BPC seen at our institution were investigated. Structural/chromosomal anomaly rates and perinatal outcomes were analysed. Among the 1,372 first trimester US carried out during the period of study, 9 cases of BPCs (0.6%) have been diagnosed. Average echographic term of diagnosis was of 12 weeks + 3 days. At US, the size and the anatomy of the vermis were normal. However, a anti-clockwise rotation was observed. The cisterna magna' s size was normal. MRI was performed in 4 cases at diagnosis; it confirmed the normal position and anatomy of the vermis and the absence of cysts in the posterior fossa. In 7 fetuses, BPC was isolated (77.8%). On the follow-up, the BPC had disappeared. Fetal karyotype was normal. After birth, normal postnatal anatomic findings was found. In 2 fetuses, associated anomalies have been detected (22.3%), consisting of heart anomalies. Karyotype confirmed the existence of trisomy 21 for both cases and a therapeutic termination of pregnancy was carried out. In case of fetal BPC, associated anomalies must be detected, and a karyotype performed. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.