What are the symptoms of autoimmune pancreatitis (AIP)?

From the Guidelines

Autoimmune pancreatitis (AIP) typically presents with symptoms such as jaundice, weight loss, and an elevated CA 19-9 level, which can be similar to those of pancreatic cancer, but can be effectively treated with corticosteroids 1. The symptoms of AIP can be diverse and may include:

• Jaundice, which is a common symptom due to the obstruction of the bile duct
• Weight loss, which can be significant and is often one of the primary concerns for patients
• Abdominal pain, although this is not always present and can vary in severity
• Elevated serum immunoglobulin (Ig) G levels, with an elevated serum IgG4 level being the most sensitive and specific laboratory indicator 1
• Diffuse pancreatic enlargement, a pancreatic ductal stricture, or a focal pancreatic mass, which can be observed on abdominal CT scans Key characteristics of AIP include:
• Prominent lymphocytic infiltration of the pancreatic parenchyma with associated fibrosis, which are cardinal histologic features of the disease 1
• A sausage-shaped enlargement of the pancreas surrounded by a capsule-like peripheral rim, which is the classic appearance on abdominal CT scans in patients with diffuse pancreatic involvement 1 It is essential to distinguish AIP from pancreatic cancer to avoid unnecessary surgery and prevent delay in the initiation of appropriate treatment, such as corticosteroids 1.

From the Research

Symptoms of Autoimmune Pancreatitis (AIP)

The symptoms of AIP can vary, but common presentations include:

• Obstructive jaundice 2, 3, 4, 5
• Abdominal pain, often mild epigastric pain 2, 6, 5
• Weight loss 2, 3, 6, 5
• Diabetes mellitus 5
• Pancreas head mass mimicking pancreatic cancer 2
• Distal common bile duct (CBD) stricture 2, 4

Clinical Characteristics

AIP can be characterized by:

• Diffuse or focal enlargement of the pancreas without peripancreatic fat infiltration 2, 6, 5
• Narrowing of the main pancreatic duct (MPD) 2, 3, 6
• Elevation of serum gamma globulin, or immunoglobulin G (IgG) 2, 3, 5
• Presence of autoantibodies, such as antibodies against lactoferrin and carbonic anhydrase 5
• Lymphoplasmacytic infiltration and dense fibrosis on histopathology 2, 3, 6

Types of AIP

There are two distinct types of AIP:

• Type 1 AIP: characterized by elevated IgG4 levels, often associated with extrapancreatic manifestations of IgG4-related disease 3, 4, 6
• Type 2 AIP: characterized by granulocytic epithelial lesions, often associated with inflammatory bowel disease 3, 4, 6