AB211. SOH26AB_0283. Case report of occult bile duct papillary carcinoma: an unanticipated diagnosis after laparoscopic cholecystectomy

Background: Papillary carcinoma of the bile duct is a rare biliary malignancy, often presenting with nonspecific symptoms or mimicking benign biliary disease. Preoperative diagnosis is challenging, and incidental detection following routine procedures is uncommon.

Case Description: We report the case of 65 years old patient who underwent an uncomplicated laparoscopic cholecystectomy for presumed benign gallbladder pathology. Intra-operative findings were unremarkable, and there was no suspicion of malignancy except slightly thickened gall bladder wall. Unexpectedly, postoperative histopathology revealed features of papillary carcinoma arising from the extrahepatic bile duct, with involvement detected on the cystic duct margin. Subsequent imaging and multidisciplinary evaluation confirmed an isolated lesion without distant spread. The patient is offered definitive surgical management with bile duct excision and Roux-en-Y hepaticojejunostomy. This case underscores the diagnostic difficulty of occult biliary tract malignancy and highlights the potential for incidental detection after routine cholecystectomy. Papillary carcinoma, although associated with a comparatively favourable prognosis due to its exophytic growth pattern, requires timely recognition to enable curative resection. Awareness of subtle pathological cues, diligent specimen assessment, and prompt referral to hepatobiliary services are essential in optimizing outcomes.

Conclusions: Occult bile duct papillary carcinoma may present without clinical or operative indicators, emphasizing the importance of histopathological vigilance. This case reinforces the need for high suspicion in atypical findings and demonstrates the value of a multidisciplinary approach in managing rare biliary malignancies.

Keywords: Cholecystectomy; cystic duct cancer; gall stones; biliary malignancy; case report