EP06.64: Megacystis: do we already know everything?

Fetal megacystis is not a simple diagnosis in terms of predicting outcomes. Even in cases of spontaneous resolution, obstructive uropathy may develop, leading to impaired renal function after birth. This study provides an overview of cases of fetal megacystis, associated structural abnormalities, and outcomes. This was a retrospective study in the antenatal fetal care room of MCCH52 maternity hospital. Ultrasound findings and associated structural abnormalities were collected for each case. Available postpartum and pathological studies were used to establish the final diagnosis. Cases of early megacystis were included in the study. Diagnosis criteria: ultrasound examination period 11+0 - 13+6 weeks of pregnancy, longitudinal diameter of the bladder ≥ 7 mm. For the period September 2021 - September 2023 8413 1st prenatal screenings were carried out. 5 cases of early fetal megacystis were registered. At the time of diagnosis: mean maternal age 33 years, mean gestational age at diagnosis 12+4 weeks. During the initial study, megacystis was isolated in 3 cases. In 1 case, a facial cleft was detected in combination with megacystis. Based on the results of amniocentesis, trisomy 13 was diagnosed, the pregnancy was terminated. Prune Bell syndrome was diagnosed in 1 case, the pregnancy was terminated. Pregnancies with isolated megacystis were prolonged. Regression of bladder size was noted, but in 2 cases hydronephrosis and megaureter developed in the second trimester. The diagnoses were confirmed postnatally, observation is being carried out, and no surgical correction is required yet. Fetal megacystis is a relatively simple diagnosis to make but presents a challenge from a counselling perspective due to its varied etiology and possible clinical course.