201 Biliary Cystadenoma: Correlation Between Radiological Findings and Histopathology in a Tertiary HPB Centre

Abstract Aim To evaluate the correlation between radiological imaging findings and histopathological features in biliary cystadenoma (BCA) and cystadenocarcinoma (BCAC), and to identify imaging predictors of malignant transformation. Background Biliary cystadenoma (BCA) is a rare cystic neoplasm of the liver, with occasional involvement of the extrahepatic bile ducts. It carries a recognised risk of malignant transformation into biliary cystadenocarcinoma (BCAC). Radiological appearances are frequently non-specific, making differentiation from benign hepatic cystic lesions challenging. Moreover, imaging features have not been reliably correlated with malignant potential. Method We performed a retrospective review of histopathology records at our institution to identify patients who underwent resection for BCA or BCAC between 2010 and 2023. All cases were discussed in a hepatopancreatobiliary multidisciplinary team (MDT) meeting, and decisions for surgical resection were based on CT and MRI findings. Radiological images were retrieved and correlated with histopathological features. Results Fifty-five cases of resected BCA or BCAC were identified. All lesions were cystic in nature. Multiloculation was observed in 47%, septal wall thickening in 38%, and solid components or nodularity in 25%. Among cases with a final diagnosis of BCAC, 80% exhibited solid components on imaging, making this the most indicative radiological feature of malignancy. Conclusions BCA and BCAC are rare hepatic lesions. Accurate radiological interpretation is key to distinguishing them from benign cystic liver disease and to identifying malignant transformation. The presence of solid components is a strong radiological predictor of BCAC. Referral to high-volume hepatopancreatobiliary centres is recommended for suspected cases to ensure appropriate management.