297 An Exceptionally Rare Diagnosis Following Cholecystectomy for Biliary Stricture and Jaundice: Yet Another Case of Adenomyomatous Hyperplasia of the Extrahepatic Bile Duct

Introduction/Objective Adenomyomatous hyperplasia (AH) is a rare, benign epithelial proliferation, commonly affects the gallbladder. Occurring in the extrahepatic bile duct is extremely rare and mimics malignancy. Due to limited preoperative diagnostic accuracy and unnecessary aggressive surgeries, making diagnosis and management particularly challenging in these cases. Methods/Case Report A 67-year-old woman experienced recurrent jaundice and elevated liver function tests (LFTs) over five years. During this time, she was also diagnosed with chromophobe renal cell carcinoma and underwent a right nephrectomy. Imaging revealed progressive intrahepatic biliary strictures and multicytic lesions, suggesting sclerosing cholangitis or intraductal papillary mucinous neoplasm. Over 20 therapeutic endoscopies with stent replacements, were ineffective. Negative hepatitis and autoimmune panels, non-malignant Fine-Needle Aspirations (FNAs), led to consideration of liver transplant. Eventually, cholecystectomy with unremarkable gallbladder and extrahepatic bile duct excision with thickened and occluded lumen were performed. Histology revealed AH of the extrahepatic bile duct with lymphoplasmacytic cholecystitis. Postoperatively, LFTs normalized, symptoms improved, and aggressive treatments avoided. Results NA Conclusion 24 cases of extrahepatic bile duct AH reported, mimicking malignancy. Diagnosis often requires major surgery due to unclear pathogenesis and inconclusive imaging or FNAs. Our five-year case emphasizes the need for improved diagnostics and multidisciplinary care to prevent unnecessary procedures and enhance timely, individualized treatment strategies.