Type 2 autoimmune pancreatitis (AIP) typically presents with diffuse or focal enlargement of the pancreas; however, its diverse clinical presentation has not yet been clarified. We herein described a 46-year-old man with a 1-month history of
ulcerative colitis who presented with imaging features of a mass-like lesion in the pancreatic body with upstream duct dilatation and serum CA19-9 elevation. He underwent laparoscopic distal
pancreatectomy with
splenectomy for suspected
malignancy. Histologically, the area radiologically suspected to be duct dilatation consisted of necrotic tissue, in which the disrupted main pancreatic duct was involved. The area radiologically suspected to be the mass lesion showed features of
pancreatitis without discrete mass. In addition, several ducts showed neutrophilic duct injury similar to granulocytic epithelial lesions observed in
type 2 AIP. Immunohistochemistry revealed the aberrant expression of
IL-8 in the pancreatic ductules and infiltrating CD3-positive T-lymphocytes, findings recently identified in
type 2 AIP. The present case is not typical for either
type 2 AIP or other known conditions, but extreme examples of
type 2 AIP may present with ductal obstruction because of severe neutrophilic duct injury.
IL-8 immunostaining may also assist in establishing a diagnosis of
type 2 AIP with an atypical presentation.