Strategy for Differentiating Autoimmune Pancreatitis From Pancreatic Cancer

Objectives: It is of utmost importance that autoimmune pancreatitis (AIP) be differentiated from pancreatic cancer (PC) because some AIP cases undergo unnecessary laparotomy or pancreatic resection on suspicion of PC. This study aimed to develop an appropriate strategy for differentiating between AIP and PC. Methods: Clinical, serological, and radiological features of 17 AIP patients forming a masslike lesion on pancreas head and 70 patients with pancreatic head cancer were compared. Results: Numerous findings can be used to distinguish between AIP and PC, and the following are more likely in AIP: fluctuating jaundice; elevated serum IgG4 levels; delayed enhancement of the enlarged pancreas and a capsule-like low-density rim on computed tomography; long or skipped narrowed portion with side branches of the main pancreatic duct without upstream dilatation on endoscopic retrograde pancreatography, extrapancreatic lesions, such as stenosis of the intrahepatic bile duct, salivary gland swelling, and retroperitoneal mass; and responsiveness to steroid therapy. Conclusions: In elderly male patients presenting with obstructive jaundice and a pancreatic mass, AIP should be considered in the differential diagnosis. Based on a combination of clinical, serological, and radiological findings, AIP can be differentiated from PC. An algorithm for management of patients with a masslike lesion on pancreas head is presented.