Imaging findings to differentiate Mass-forming Pancreatitis and Pancreatic Malignancy

 

Imaging findings	Mass-forming Pancreatitis	Pancreatic Malignancy
Duct-penetrating sign	Smooth narrowing of pancreatic duct which is seen traversing  a pancreatic mass without obstruction strongly favors the diagnosis of an inflammatory mass   The duct may be smoothly narrowed or of normal caliber.   The duct-penetrating sign is 96% specific for an inflammatory pancreatic mass, with sensitivity of 85% and accuracy of 94%.	Not seen
Collateral Duct Dilatation	Collateral duct or side-branch dilatation in the uninvolved or distal pancreas supports an inflammatory cause   Dilatation of pancreatic duct side branches is thought to be due to a traction effect from fibrosis in a patient with chronic pancreatitis.	Not seen
Displaced Calcifications in Chronic Pancreatitis	Usually absent	Peripheral displacement of pancreatic parenchymal calcifications commonly seen in chronic pancreatitis calcifications may indicate a new underlying malignancy
Double Duct Sign	The double duct sign is nonspecific and can develop secondary to inflammatory processes in the pancreas as well as other nonmalignant conditions	Simultaneous dilatation of the common bile duct and pancreatic duct, known as the double duct sign favors a malignant lesion   Seen in malignancies involving the head of the pancreas in up to 77% cases
Duct-to-Parenchyma Ratio	Usually < 0.34	Pancreatic duct-to-parenchyma ratio of greater than 0.34 strongly favors malignancy.   It is due to marked upstream pancreatic ductal dilatation with marked parenchymal atrophy, which are the imaging hallmarks of pancreatic adenocarcinoma
Vessel Encasement and Vessel Deformity	Uncommon but may be seen in inflammatory conditions such as autoimmune pancreatitis	Soft-tissue attenuation that encases the adjacent vasculature is highly suggestive of the extra glandular spread of pancreatic adenocarcinoma and is crucial in determining tumor resectability.   SMV teardrop sign, a teardrop-shaped deformity of the SMV, is highly indicative of SMV encasement
SMA-to-SMV Ratio	< 1 in acute pancreatitis	> 1 in malignancy. Not sensitive or specific.

 

Reference:

1. Wolske KM, Ponnatapura J, Kolokythas O, Burke LMB, Tappouni R, Lalwani N. Chronic Pancreatitis or Pancreatic Tumor? A Problem-solving Approach. Radiographics. 2019 Nov-Dec;39(7):1965-1982. doi: 10.1148/rg.2019190011. Epub 2019 Oct 4. PMID: 31584860.