The in-utero diagnosis of choledochal cyst: can postnatal imaging predict benefit from early surgical intervention?

Background: Infants prenatally suspected of having a choledochal cyst (CDC) typically undergo ultrasound imaging shortly after birth. This study sought to evaluate features on the initial postnatal ultrasound (IPU) that could identify newborns at risk for early complications. Methods: Following IRB approval, patients from four US fetal centers with prenatal suspicion for CDC and postnatal imaging from 2000 to 2017 were reviewed. Imaging and clinical courses were assessed. Results: Forty-two patients had prenatal ultrasounds suspicious for CDC. Nineteen (45.2%) were excluded due to diagnostic revision (n = 9), cyst resolution (n = 5), lack of IPU measurements (n = 3), or lack of follow-up (n = 2). The 23 remaining patients were included in the study. Of these, five (21.7%) developed symptoms at a median age of 16.5 days (IQR 16-19 days), and 18 (78.3%) remained asymptomatic throughout the first year after birth. Five patients (21.7%) had cysts >= 4.5 cm on IPU (Symptomatic: n = 3; Asymptomatic: n = 2). Eighteen patients (78.3%) had cysts < 4.5 cm on IPU (Symptomatic: n = 2; Asymptomatic: n = 16). An IPU cyst size >= 4.5 cm was associated with neonatal symptom manifestation (p = 0.048), with 88.9% specificity (95% CI 65.3-98.6%) and 60% sensitivity (95% CI 14.7-94.7%). Conclusions: In newborns with prenatally diagnosed CDC, a cyst size >= 4.5 cm on IPU is associated with symptom development during the first month after birth and therefore early cyst excision is recommended.