Metachronous cholangiocarcinoma following pancreaticoduodenectomy and the potential role of a migrated pancreaticojejunal stent: a case report and review of the literature.

Metachronous cholangiocarcinoma following curative surgery for periampullary neoplasia is a rare but serious long-term complication that poses significant diagnostic and management challenges. We report the case of a 62-year-old male who developed hilar cholangiocarcinoma 9 years after undergoing a pancreaticoduodenectomy (Whipple procedure) for an ampullary adenoma. The patient was initially diagnosed with a duodenal papillary villous tubular adenoma showing moderate dysplasia in 2015 and underwent curative resection, with no evidence of recurrence during subsequent follow-up. In 2024, he presented with obstructive jaundice and imaging findings revealing a hepatic hilar mass with intrahepatic biliary dilation. A biopsy confirmed a poorly differentiated cholangiocarcinoma (Klatskin tumor). Crucially, intraoperative exploration identified migration of the internal pancreaticojejunostomy stent to a site adjacent to the biliary-enteric anastomosis. Immunohistochemical analysis demonstrated wild-type P53 expression and proficient mismatch repair function, supporting a sporadic rather than hereditary origin. This case underscores the importance of considering second primary malignancies in patients with late-onset biliary obstruction after pancreaticoduodenectomy. We propose that the migrated and retained pancreatic stent may have acted as a chronic local irritant, potentially exacerbating inflammation and contributing to carcinogenesis within the biliary-enteric anastomotic milieu, thereby highlighting a possible long-term risk associated with indwelling surgical stents.