Liver histology in choledochal cyst- pathological changes and response to surgery: the overlooked aspect?

Histological changes in the liver in cases of choledochal cyst are seldom reported. The severity of liver pathology has an impact on the presentation, course and prognosis of hepatobiliary lesions. This study aims to record the histological changes in the liver and response to surgery in patients with choledochal cyst and to correlate these with the clinical symptoms and recovery.

All children <12 years diagnosed with choledochal cyst were evaluated clinically, radiologically and biochemically at presentation. Excision of the cyst with intra-operative liver biopsy was done. Liver biopsy was repeated after 6 months of surgery. Both the liver biopsies were compared objectively in terms of hepatocellular damage, cholestasis, parenchymal inflammation, bile duct inflammation, bile duct proliferation, portal fibrosis and central venous distension with appropriate statistical tests. Clinical presentation and recovery were correlated with grades of liver pathology.

Forty-six patients were included. Pathological damage was observed in all the livers preoperatively. Post-operatively, significant resolution of histological changes was seen in hepatocellular damage (p < 0.0001), parenchymal inflammation (p = 0.0001), cholestasis (p = 0.0003) and bile duct proliferation (p = 0.0001). Portal fibrosis did not resolve. Central venous distension worsened. Severity of damage correlated significantly with younger age, symptom severity, anomalous pancreatico-biliary junction (APBJ) and obstructive biliary clearance on Tc-99 HIDA scan. Post-operative bile duct proliferation, bile duct inflammation and portal fibrosis were associated with cholangitis, re-do surgery and obstructive Tc-99 HIDA scan clearance in the post-operative period.

All patients with choledochal cyst show pathological changes in liver of varying severity. More severe symptoms, younger age and APBJ are associated with higher degree of liver damage. Except portal fibrosis and central venous distension, all other pathological changes regress after surgery. Regression can be hindered by post-op cholangitis, obstructive biliary clearance and post-op IHBR dilatation.