2026 Volume 64 Issue 3 Pages 440-454
Invasive pancreatic ductal carcinoma arises in the pancreatic duct epithelium, destroys the main pancreatic duct wall, and invades the pancreatic parenchyma. Therefore, the disappearance of linear hyperechoic areas in the pancreatic duct wall is an ultrasound finding that strongly suggests pancreatic cancer. However, even if a tumor occurs within the pancreatic parenchyma, if the main pancreatic duct is compressed strongly, it may appear as if the pancreatic duct is interrupted. Furthermore, if the ultrasound waves hit the tumor boundary at an angle or are not focused, a tumor with a smooth boundary may appear rough.
When pancreatic cancer is discovered using ultrasound, seven items must be evaluated: (1) tumor diameter, (2) whether the tumor is contained within the pancreas, (3) whether there is vascular invasion (abdominal aorta, celiac artery, superior mesenteric artery, common hepatic artery to proper hepatic artery, portal vein to superior mesenteric vein), (4) whether there is lymph node metastasis, (5) whether there is distant metastasis, (6) whether there is ascites, and (7) intrahepatic bile duct diameter (if accompanied by obstructive jaundice). This allows for an understanding of the patient’s condition at the first step after discovery, and also leads to an assessment of the stage of the disease and the feasibility of resection.
The presence of focal pancreatic atrophy, main pancreatic duct stenosis, and distal pancreatic duct dilation is a strong indication of intraepithelial carcinoma.
To evaluate these correctly, it is important to ensure that the ultrasound waves hit the target object perpendicularly.
