Maimonides Medical Center Brooklyn, NY, United States
Neha Sharma, MBBS, Kaveh Zivari, MD, Avleen Kaur, MD, Meredith E. Pittman, MD, Rabin Rahmani, MD, Kevin Tin, MD Maimonides Medical Center, Brooklyn, NY
Introduction: Autoimmune pancreatitis (AIP) is a fibro-inflammatory disease that leads to chronic pancreatitis. AIP can mimic pancreatic cancer and its diagnosis can be challenging. Type 1 AIP is characterized by IgG4-positive plasma cell infiltration around the pancreatic duct, obliterative phlebitis, and storiform fibrosis. Type 2 AIP is characterized by granulocytic epithelial lesions and is generally without IgG4 or systemic involvement. Patients with AIP may present with painless obstructive jaundice or acute pancreatitis.
Case Description/Methods: A 46-year-old female was seen for 2 weeks of abdominal pain, jaundice, pale stools, and dark urine. Liver enzymes were elevated in mixed hepatocellular and cholestatic patterns. Serum IgG 4 was significantly elevated at 220mg/dL (N= 2-96mg/dL). CT/MRI of the abdomen with contrast, MRCP, and EUS revealed a distal common bile duct stricture, 2.4 cm hypoenhancing mass in the head / uncinate process of pancreas with the abutment of SMV. EUS biopsy was unremarkable. Due to the potential danger of not operating on such a disease, the patient underwent a Whipple procedure (Pancreaticoduodenectomy with pancreatic jejunostomy). Histopathological review of the resected region showed atrophic pancreatic parenchyma with fibrosis, plasmacytic infiltration, and abundant IgG4-expressing plasma cells, suggestive of IgG4-related sclerosing pancreatitis (Fig 1 a, b, c).
Discussion: The clinical picture of AIP depends on its subtype. Type 1 is more seen in older males, associated with high serum IgG4, and other autoimmune disorders. Type 1 can present as painless obstructive jaundice mimicking pancreatic cancer. Type 2 AIP mainly affects younger patients and is not associated with elevated IgG4. In type 2, unlike type 1 AIP, systemic autoimmune disease is not seen. Diagnosis of type 2 AIP can be very challenging and surgery may be unavoidable. Although EUS can help with the most common findings of stranding, calcification, with homogeneous echogenic mass, it is not always definitive. Due to high morbidity and mortality associated with missed diagnosis, resection may be required. If AIP is diagnosed it can be treated with high-dose steroid, rituximab, or immunomodulators such as azathioprine, mycophenolate mofetil, or methotrexate.
Figure: Pathology slides
Disclosures: Neha Sharma indicated no relevant financial relationships. Kaveh Zivari indicated no relevant financial relationships. Avleen Kaur indicated no relevant financial relationships. Meredith Pittman indicated no relevant financial relationships. Rabin Rahmani indicated no relevant financial relationships. Kevin Tin indicated no relevant financial relationships.
Neha Sharma, MBBS, Kaveh Zivari, MD, Avleen Kaur, MD, Meredith E. Pittman, MD, Rabin Rahmani, MD, Kevin Tin, MD. P0089 - Challenges of Treating Type 2 Autoimmune Pancreatitis Mimicking Pancreatic Cancer, ACG 2021 Annual Scientific Meeting Abstracts. Las Vegas, Nevada: American College of Gastroenterology.