[A case of a small pancreatic cancer with an intact main pancreatic duct].

A 56-year-old woman was admitted to our department for further evaluation of a hypoechoic mass in the pancreatic head detected by abdominal ultrasonography during a medical check-up. Abdominal and endoscopic ultrasonography demonstrated a demarcated round hypoechoic mass 15 mm in size without dilation of the main pancreatic duct, and ERP showed a normal main pancreatic duct and branch duct. Because pancreatic cancer was strongly suspected based on dynamic CT and MRI findings, she underwent pancreatoduodenectomy. Pathologically, the tumor was diagnosed as well-differentiated adenocarcinoma in the pancreatic head, 13 mm in diameter, 10mm apart from the main pancreatic duct. The main pancreatic duct was completely free of cancer cells and the origin of the cancer was considered to be the epithelium of a peripheral branch duct.