VHM11 Not All Pancreatic Masses are Cancer: Confirming the Diagnosis of AIP with Pancreatic Core Biopsies

Abstract

A 25 year old female presented with a 3 month history of abdominal pain with eating. She had such severe pain, she had stopped working and was on disability. On evaluation at an outside hospital, she was noted to have pancreatitis, a possible hypoechoic lesion in the pancreatic head on imaging, biliary sludge and a stricture in the mid common bile duct. She had a cholecystectomy and post-operatively developed worsening pain. On presentation to our hospital her lipase was 123. Further evaluation included a negative IgG4 and a negative ANA. However, she had imaging that demonstrated what appeared to be a sausage shaped pancreas with a thin duct and the possibility of autoimmune pancreatitis was raised. Endoscopic ultrasound was performed. The pancreas was diffusely homogeneous and hypoechoic with scalloped edges and had a thin pancreatic duct in both the head and body. Color Doppler imaging was used prior to needle puncture to confirm a lack of significant vascular structures within the needle path. A total of two passes were made with a 19 gauge Pro-Core biopsy needle using a transgastric approach. The needle is initially inserted into the pancreatic parenchyma and then held stationary for 30 seconds before being moved up and down a total of 4 times in order to obtain an adequate amount of pancreatic tissue. The IgG4 stain of the core biopsy specimen revealed an increased number of IgG4 positive plasma cells. Autoimmune pancreatitis is a clinical entity that can be difficult to diagnose. Imaging often demonstrates a sausage shaped pancreas and an elevated serum IgG4 may also be seen. In some cases, labs may not be suggestive of the disease. Pancreatic core tissue biopsies with IgG4 staining can assist in confirming the diagnosis.