Pancreas
Pancreatitis
Autoimmune pancreatitis

Author: Deepali Jain, M.D. (see Authors page)

Revised: 8 December 2017, last major update August 2012

Copyright: (c) 2002-2017, PathologyOutlines.com, Inc.

PubMed Search: Autoimmune pancreatitis[TI] pancreas[TIAB] free full text[sb]

Cite this page: Jain, D. Autoimmune pancreatitis. PathologyOutlines.com website. http://pathologyoutlines.com/topic/pancreasaip.html. Accessed December 15th, 2017.
Definition / general

Type 1 / lymphoplasmacytic sclerosing pancreatitis:
  • Pancreatic manifestation of IgG4 related systemic disease (BMC Med 2006;4:23)
  • Pancreas shows hypercellular lymphoplasmacytic infiltrate of interlobular stroma (91%), storiform type fibrosis, > 10 IgG4 plasma cells/high power field (typically > 50/HPF), infiltrate may extent to peripancreatic tissue
  • 75% male, older patients, often presents with jaundice; may recur within and outside pancreas
  • Associated with sclerosing cholangitis, Sj√∂gren-like syndrome, obliterative phlebitis, arterial involvement

Type 2 / idiopathic duct centric pancreatitis:
  • Confined to pancreas (i.e. not systemic)
  • Pancreas shows microabscesses and ductal ulceration (78%), granulocyte epithelial lesions, only occasional IgG4 plasma cells (< 10/HPF)
  • Often pancreatic tail cutoff sign by imaging (40%), disease recurrence uncommon
  • No gender preference, younger patients, associated with inflammatory bowel disease, not with obliterative phlebitis
  • By definition, no known cause for chronic pancreatitis (i.e. no alcohol abuse) and features of classic chronic pancreatitis (fat necrosis, pseudocysts, calcifications, dilated ducts with inspissated secretions) are absent
  • Compared to chronic pancreatitis NOS, more foci of periductal inflammation and neutrophilic microabscesses
Treatment
Gross description
  • Pancreatic mass with regional nodal swelling
  • Narrowing of main pancreatic duct
Microscopic (histologic) description
Type 1:
  • Prominent periductal and acinar lymphoplasmacytic infiltration and fibrosis around the pancreatic ducts
  • Marked acinar atrophy, phlebitis of pancreatic and portal veins
  • > 10 IgG4 plasma cells/high power field, infiltrate may extent to peripancreatic tissue

Type 2:
  • Microabscesses and ductal ulceration (78%), no IgG4 plasma cells
  • No calcifications, no fat necrosis, no cyst formation
Microscopic (histologic) images

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Type 1 cases


Type 1 cases

Type 2: small caliber ducts with granulocytic epithelial lesions

Type 1 and type 2 cases

Cytology images

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Type 1

Type 2 cases

Differential diagnosis