Mixed-type IPMN

Case contributed by Vikas Shah


A few weeks of vague upper abdominal pain. Mildly raised amylase. ? mass, ? inflammation

Patient Data

Age: 40 years
Gender: Male

CT abdomen and pelvis


Diffuse dilatation of the main pancreatic duct throughout the gland. No dilatation of side ducts. The dilatation is continuous to the ampulla (fishmouth ampulla sign). Mild peripancreatic edema with increased attenuation of surrounding fat. Mild reduction in density in the head and neck of the pancreas. No discrete peripancreatic fluid connection. Lymph nodes with an inflammatory appearance anterior to the neck of the pancreas. No focal hyper-enhancing pancreatic mass. No bile duct dilation. Normal liver and gallbladder. No splenic or portal vein thrombosis. No abnormalities elsewhere within the abdomen.

MRI pancreas


The MRI also confirms the presence of diffuse dilatation of the main pancreatic duct, and identifies dilatation of some of the side branches. There is a continuous column of T2 hyperintense signal throughout the duct and extending into the ampulla, this is the fish mouth ampulla sign. There is no nodularity within the pancreatic duct. No abnormal restriction of diffusion is identified. Inflammatory lymph nodes are present adjacent to the pancreas. There is some edema of the head and neck of the gland. 

Case Discussion

The findings here are consistent with a mixed-type IPMN. There is continuous dilatation of the entire main pancreatic duct, with a column of mucin extending into the ampulla of Vater, known as the fish mouth ampulla sign. High-risk features include dilatation of the pancreatic duct to greater than 10 mm. There are no nodules detected within the duct wall. Minimal dilatation of the side branches is appreciated only on the heavily T2 weighted on the MRI study. Some edema of the head and neck of the gland is consistent with mild acute pancreatitis related to the underlying disease process. Imaging appearances have stayed stable on serial imaging studies while surgery is awaited.

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