E0079 - Pancreatic Adenocarcinoma in the Setting of Autoimmune Pancreatitis

Heather M. Ross, BS¹, Natalia Salinas Parra, BS¹, Sarah L. Chen, BA², Kevan Josloff, BS, MPH¹, Alexis Gerber, MD³, Adnan Khan, DO^4
1Sidney Kimmel Medical College, Philadelphia, PA; ²Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, PA; ³Thomas Jefferson University Hospital, Philadelphia, PA; ⁴Thomas Jefferson University Hospital, Ballwin, MO

Introduction: Autoimmune pancreatitis (AIP) accounts for 2% of pancreatitis cases and is characterized by chronic pancreas inflammation of autoimmune etiology. Two types of AIP are recognized. Type 1 AIP is an IgG4-related disease which often affects multiple organs. Type 2 AIP is IgG4-negative and affects mainly the pancreas with a third of patients exhibiting additional manifestations. The chronic inflammatory nature of AIP may be associated with higher rates of pancreatic cancer as compared to chronic pancreatitis of other etiologies. This case demonstrates a new diagnosis of pancreatic cancer thought to be secondary to Type 2 AIP.

Case Description/Methods: A 35-year-old female with a past medical history of diverticulitis and chronic pancreatitis of suspected autoimmune etiology presented to the hospital with persistent abdominal pain. An abdominal ultrasound demonstrated a hypoechoic pancreas with focal dilation of the main pancreatic duct (PD). IgG4 was within normal limits. An endoscopic ultrasound (EUS)/endoscopic retrograde cholangiopancreatography (ERCP) with fine needle biopsy (FNB) demonstrated signs of pancreatic inflammation and PD dilation. Biopsy was negative for malignancy. She was discharged on oxycodone and gabapentin and was readmitted without resolution of abdominal pain. On readmission, a CT abdomen/pelvis demonstrated a hypo-enhancing infiltrating lesion in the pancreatic head and uncinate process measuring 2.8 x 2.7 cm with vascular involvement. Ca-19.9 was within normal limits. EUS/ERCP with FNB demonstrated hypoechoic expansion of the pancreas head with PD dilation. Biopsy was positive for pancreatic ductal adenocarcinoma determined to be stage III and unresectable. Treatment with chemotherapy was initiated and currently ongoing at three month follow up.

Discussion: AIP and pancreatic cancer have similar presentations and must be clinically distinguished for appropriate treatment. There are many case reports of misdiagnosed pancreatic cancer later determined to be AIP by negative biopsy, however, there are few reported cases of AIP associated pancreatic cancer with positive biopsy. AIP is a chronic state of pancreas inflammation which may represent a pre-malignant process. This case demonstrates a patient with Type 2 AIP and negative biopsy who subsequently developed biopsy proven pancreatic cancer. Patients with Type 2 AIP may require close follow up for early detection of AIP induced pancreatic cancer. Further investigation is needed to determine the pre-malignant potential of AIP.


Disclosures:


Heather M. Ross, BS¹, Natalia Salinas Parra, BS¹, Sarah L. Chen, BA², Kevan Josloff, BS, MPH¹, Alexis Gerber, MD³, Adnan Khan, DO⁴. E0079 - Pancreatic Adenocarcinoma in the Setting of Autoimmune Pancreatitis, ACG 2022 Annual Scientific Meeting Abstracts. Charlotte, NC: American College of Gastroenterology.