Differentiation between cystic biliary atresia and choledochal cyst: A retrospective analysis

Cystic biliary atresia (CBA) can be easily misdiagnosed as choledochal cyst (CC). Some patients have already progressed to severe liver fibrosis and missed the optimal surgical time, when the differential diagnosis is made. We aim to determine the differentiation between CBA and CC, and to validate the value of aspartate aminotransferase-to-platelet ratio index (APRI) in the assessment of liver fibrosis and prediction of post-operative outcome for infants with biliary cystic malformations (BCMs).

Clinical data of children (categorised into CBA and CC groups) with BCMs were analysed retrospectively. Biochemical indicators together with B-ultrasound examinations and the degree of liver fibrosis were analysed, and those with statistical difference between the two groups were selected for diagnostic receiver operating characteristic curve analysis.

The parameter that showed the highest accuracy with a significant diagnostic performance for differentiating CBA from CC was cyst size. Liver assessment at operation was categorised into mild fibrosis and moderate-to-severe fibrosis. The APRI values were much lower in the mild fibrosis groups than in the moderate-to-severe fibrosis group (0.4 ± 0.2 vs. 1.4 ± 0.8, P < 0.001). A cut-off value of 0.96 (area under the curve 0.92, P < 0.001) showed a sensitivity of 81.3% and a specificity of 100% for moderate-to-severe fibrosis. Lower APRI value was correlated with short-term post-operative bilirubin clearance.

There is still certain difficulty in the early identification of CBA and CC clinically. Liver fibrosis could occur as early as infantile period in both CBA and CC. In infants with BCMs, APRI can be used as a non-invasive method to detect liver fibrosis in early stages.