Autoimmune pancreatitis; This is a literature report.  A 54-year-old male patient received BNT162b2 (BNT162B2), as dose 2, single (Batch/Lot number: unknown) for covid-19 immunisation. The patient with a history of chronic stable sarcoidosis and ulcerative colitis in surgical remission who presented with a 3 week history of decreased appetite, abdominal pain, fatigue, and 25-pound unintentional weight loss. He reported no history of diabetes, pancreatic cancer, or pancreatic surgery. He was not on any immunosuppressants and had no recent medication changes. He had received the second dose of Pfizer/BioNTech COVID-19 mRNA vaccine approximately 1 month before current presentation. On admission, the patient had vital signs within normal limits. On physical examination, he seemed dehydrated. Computed tomography (CT) was significant for diffusely enlarged pancreas with peripancreatic fat surrounding the tail of the pancreas. He was treated with intravenous fluids and discharged from the emergency department with recommendation to follow-up with his primary care provider. A few days later, he presented to the emergency department with jaundice and scleral icterus. Laboratory tests were significant for hypovolemia, hyperglycemia, total bilirubin of 10.5mg/dL (reference range 0.2-1.0mg/dL), direct bilirubin 7.9 mg/dL (reference range 0-0.2 mg/dL), aspartate aminotransferase of 137 U/L (reference range 10-55 U/L), alanine aminotransferase of 515 U/L (reference range 10-55 U/L), alkaline phosphatase 630 U/L (reference range 45-128 U/L), and lipase 240 U/L (reference range 13-60 U/L). The immunoglobulin G4 (IgG4) level was 287.0 mg/dL (reference range 4.0-86.0 mg/dL). A repeat CT scan demonstrated distended pancreatic parenchyma with peripancreatic stranding with segments of biliary ductal dilation. He underwent a magnetic resonance cholangiopancreatography which showed dilated bile ducts to the level of the head of the pancreas where there was an abrupt truncation of the extrahepatic common duct. The pancreas was diffusely enlarged with some irregular beading and narrowing of the main pancreatic duct. Minimal amount of peripancreatic fluid pattern was noted. On endoscopic retrograde cholangiopancreatography (ERCP), the lower third of the main bile duct contained a single severe stenosis 20-25 mm in length and a biliary stent was placed. Brush cytology from the common bile duct was negative for malignancy. Endoscopic ultrasound was performed and pancreatic parenchyma was diffusely abnormal with lobularity, generalized hypoechoic gland, and hyperechoic foci without shadowing. The pancreatic duct was irregular in contour. Fine needle biopsies were obtained from the pancreatic body. Immunohistochemical tests showed IgG and IgG4 positive plasma cells. There were 18 IgG4-positive plasma cells with a calculated IgG IgG4 ratio of 0.7, which is suggestive of an IgG4 related chronic pancreatitis, also known as type 1 AIP. Inflammatory cells consisted predominantly of lymphocytes and plasma cells and occasional eosinophils. The patient was started on a 3 week prednisone taper starting with 40 mg. Repeat laboratory work showed normalization of liver enzymes and IgG4. Repeat magnetic resonance cholangiopancreatography showed strictures in the distal common bile duct with interval improvement. Repeat ERCP showed improvement of the lower third of the main bile duct with a focal area of stenosis at 8 mm in length. Two biliary stents were placed for serial dilation. On the 9 month followup, he had gained his weight back and reported complete resolution of abdominal pain and fatigue.; Sender's Comments: Based on available information and temporal association, a possible causal relationship cannot be excluded the possibility that the suspect vaccination of bnt162b2 triggered the reported event Autoimmune pancreatitis under the medical background of ulcerative colitis which could be the confounding factor to the event onset. The impact of this report on the benefit/risk profile of the product is evaluated as part of Pfizer procedures for safety evaluation, including the review and analysis of aggregate data for adverse events. Any safety concern identified as part of this review, as well as any appropriate action in response, will be promptly notified to Regulatory Authorities, Ethics Committees, and Investigators, as appropriate.