Sudden detection of pyriform sinus carcinoma during endoscopic retrograde cholangiopancreatography.

Iatrogenic trauma and perforation are among the most concerning complications of endoscopic retrograde cholangiopancreatography (ERCP). A 76-year-old man presented for management of obstructive jaundice caused by pancreatic cancer. The ERCP was planned for further evaluation of pancreatic cancer and endoscopic biliary drainage. The ERCP scope could not pass because of resistance during the initial attempt to insert it through the pyriform sinus. After two attempts, mild bleeding occurred in the oral cavity, and the ERCP scope was successfully inserted in the esophagus. Tissue debris was observed in the esophagus; however, it was considered attributable to damage during insertion. Because passage was difficult, we placed a guidewire deep in the duodenum to ensure an accurate route and removed the ERCP scope. Then, we switched to direct-view esophagogastroduodenoscopy (EGD) and observed the pyriform sinus. EGD showed an irregular ridge and stenosis, which were determined to comprise a pyriform sinus tumor. Tissue fragments at the ERCP insertion site were retrieved for pathological examination. The ERCP scope was inserted using a guidewire, and biliary drainage was completed. When unexpected resistance is noticed, endoscopic manipulation should be stopped, and a detailed evaluation should be conducted. Endoscopists, particularly trainees with limited procedural experience, should be vigilant of these potential complications.