EP12.29: Antenatally diagnosed abdominal cysts: 11 years' experience

Abstract

The aim of this study was to assess the antenatal course of fetal abdominal cysts diagnosed between 2005 and 2016 at our institution. We identified all fetal abdominal cysts diagnosed between 2005 and 2016 using our ultrasound database. The fetuses were monitored during the pregnancy to assess the antenatal course of the cyst. The gestational age (GA) at diagnosis and all the characteristics of the cyst were recorded (size, location, wall thickness, echogenity, septation, vascularity). There were 80 cases of abdominal cysts identified and 85% had follow up scans during the pregnancy. The median GA at diagnosis was 28+4 weeks (range 11+0 – 38+3 weeks). Most of the cysts (87%) were isolated. The cysts were located in the pelvis (52%), the right abdomen (25%) and in the left abdomen (23%). The large majority of cysts were thin-walled (96%), anechoic (96%), unilocular (91%) and avascular (100%). Fetal intervention by cyst aspiration was performed in 6% of cases and of those 60% disappeared whilst 40% persisted in the follow-up scans. During the antenatal course, 28% resolved spontaneously in-utero; 30% reduced in size; 10% were stable; and 32% increased in size. Cysts under 20 mm in size at the initial scan increased in size in 41% of the cases while cysts over 40 mm increased in 20% of the cases. Abdominal cysts frequently present isolated. The large majority are unilocular, anechoic and thin-walled. Rarely fetal intervention is required. In our series, one third increased in size during follow-up, whilst two thirds resolved, reduced or were stable in size. Cysts under 20 mm grew more than cysts over 40 mm.