Adenocarcinoma developed from remnant cystic duct after cholecystectomy

BACKGROUND Cystic duct adenocarcinoma is a rare disease because the cystic duct has a short length and a narrow cavity. Cystic duct adenocarcinoma accounts for 8% of all gallbladder adenocarcinoma; of these, adenocarcinoma that develops from the remnant cystic duct after cholecystectomy is extremely rare. We report a case of incidentally detected adenocarcinoma that developed from the remnant cystic duct in a patient with history of cholecystectomy. CASE PRESENTATION A 74-year-old Korean woman visited our hospital with abdominal pain. Her past medical history included cholecystectomy for acute cholecystitis with gallstones 10 years previously. Imaging of the abdomen demonstrated inflammation of the remnant cystic duct with multiple impacted stones. Complete removal of the remnant cystic duct with stones was performed. The pathologic report showed severe inflammation with abscess formation and an unexpected adenocarcinoma that appeared to invade the perimuscular connective tissue. The second operation (confirmation of the resection margin of the remnant cystic duct, wedge resection of the liver, and lymphadenectomy) was performed due to suspicion of pT2. There were no cancer cells in the resection margin of the remnant cystic duct, liver, or lymph nodes (0/6). The final histopathological diagnosis was pT2N0M0. She recovered without any complications. The patient is still living 1 year after surgery without recurrence or metastasis. CONCLUSIONS We report a rare case of adenocarcinoma that developed from the remnant cystic duct in a patient who underwent cholecystectomy.