Avoiding Unnecessary Surgery in Autoimmune Pancreatitis: Lessons From a Four-Patient Case Series and Literature Review.

Autoimmune pancreatitis (AIP) is an inflammatory disease that may be mistaken for pancreatic cancer, especially when there is a focal lesion in the pancreatic head. It often involves biliary strictures and occasional tumor marker elevations, causing confusion with malignancy. An incomplete assessment might lead to unwarranted surgery for what is actually an inflammatory process. By combining imaging, histopathology, IgG4 measurement, and the clinical response to steroids, physicians can reach the correct diagnosis more reliably. We describe four adults, ages 64 to 84, who had obstructive jaundice, biliary dilation, and imaging findings suggesting a possible pancreatic head tumor. Tumor marker levels varied; some were elevated, while others were unremarkable. In two instances, imaging raised concerns about vascular involvement. Endoscopic ultrasound-guided biopsies showed lymphoplasmacytic inflammation without malignant cells, and all patients had elevated IgG4 levels that decreased with steroid therapy. Each individual underwent endoscopic biliary stenting and began a course of prednisone, leading to a return of normal liver function and improvement in imaging findings. Two required short-term additional stent management for persistent strictures, and three underwent gallbladder removal due to associated disease. All four avoided major pancreatic surgery and had a favorable clinical course. These cases show the importance of a methodical workup that includes IgG4 assessment and biopsy confirmation. Steroid therapy can resolve clinical and radiologic abnormalities once AIP is recognized. This approach spares many patients from extensive operations when their presumed neoplasm is, in reality, an autoimmune condition.