[A Case of Appendiceal Metastasis from Hilar Cholangiocarcinoma with Acute Perforated Appendicitis and Cholecystitis].

An 88-year-old woman had been diagnosed with hilar cholangiocarcinoma for 3 years since she received metallic stents for malignant biliary obstruction, and observed without any aggressive medical treatment. She was admitted to our hospital for further investigation of her abdominal pain. Abdominal CT showed an enlarged gallbladder, fluid collection in the right paracolic gutter, and swollen appendix. Laboratory tests showed high-grade inflammation. She was diagnosed with acute perforated appendicitis with acute cholecystitis. Laparoscopic cholecystectomy and appendectomy were performed. Perforation was confirmed intraoperatively in the appendix wall and accumulation of pus was found in the right paracolic gutter. There were no macroscopic findings of metastasis and peritoneal dissemination. Microscopic examination of the resected appendix showed adenocarcinoma cells positive for CK7 and negative for CK20 and CDX2, and were predominantly infiltrated from the muscular layer to the serosa of the appendix wall, with a diagnosis of appendiceal metastasis from hilar cholangiocarcinoma. Metastatic appendiceal carcinoma is rare, and appendiceal metastasis from hilar cholangiocarcinoma is extremely rare. Herein, we report a rare case of metastatic appendiceal carcinoma from hilar bile duct cancer with acute perforated appendicitis and cholecystitis along with findings of previous literature.