IgG4 PancreatitisDr Chan Lok Lam Laura

United Christian Hospital

JHSGR 6th Aug, 2011

IgG4 pancreatitisRecently described disorder with protean

manifestations

Important diagnostic consideration in patients with obstructive jaundice associated with pancreatic mass lesion

Mimics pancreatic cancer clinically and radiologically

Dramatic response to steroid

Correct diagnosis allows medical treatment and avoids major surgery

IgG4 pancreatitis = autoimmune pancreatitis?

In previous literature YES!

Concept evolving

Autoimmune pancreatitis (AIP)

Type I AIP (IgG4 pancreatitis)Pancreatic

manifestation of systemic IgG4-related disease

Type II AIPSpecific pancreatic disease occasional association with

ulcerative colitis

IgG4 pancreatitisChronic inflammatory disease of presumed

autoimmune origin

Pathogenesis not well understood

Lymphoplasmacytic infiltration with abundant IgG4 positive cells

Inflammatory process responds well to steroid therapy

EpidemiologyUncommon

0.82 per 100,000 patients in a Japanese nationwide survey (2002)

4.6-6% in patients with chronic pancreatitis

3-5% undergoing pancreatic resection for suspected pancreatic cancer

EpidemiologyElderly Male

Extra-pancreatic manifestations

Biliary strictures

Sclerosing sialadenitis

Retroperitoneal fibrosis

Sclerosing cholecystitis

Interstitial nephritis

Diffuse lymphadenopathy

Characteristic lymphoplasmacytic infiltrate rich in IgG4-positive cells

Can precede/ accompany / follow pancreatic involvement

Clinical presentationPainless obstructive jaundice (65%)

Vague abdominal pain

Weight loss

Exocrine insufficiency (88%)

Endocrine dysfunction (67%)

Laboratory findingsAmylase/ lipase: normal/ mildly elevated

Gamma globulin, total IgG, IgG4Commonly elevatedSerum IgG4 :

140 mg/dl: Sensitivity 76%; Specificity 93% 280 mg/dl: Sensitivity 53%; Specificity 99% Elevated in 7-10% cases of Pancreatic CA

(usually mild)

AutoantibodiesANA, RF: elevated (non-specific)

RadiologicalCT/ MRI:

Diffuse enlargement of the entire pancreas ‘sausage-like’

Low density capsule-like rim due to inflammation and fibrosis

Delayed contrast enhancement

CT/ MRIFocally enlarged pancreas ‘inflammatory mass’

ERCP/ MRCPDiffuse narrowing of main pancreatic duct

ERCP/ MRCPSegmental narrowing of main pancreatic duct

Biliary stricture ( can occur anywhere )

DifferentiationIgG4 Pancreatitis CA Pancreas

Narrowing of MPD > 1/3 or > 3cm

Pancreatic duct dilatation

Skipped, narrow lesions of MPD

Abrupt pancreatic duct cut-off

Side branches from narrow portion of MPD

Upstream pancreatic atrophy

Stricture of intrahepatic ducts

EUS guided FNACDetecting

adenocarcinomaSensitivity 70-90%Negative bx does not

rule out CA

Not for diagnosis of IgG4 pancreatitis Inadequate cellsLack of architecture

EUS guided core biopsy

Allow diagnosis of IgG4 pancreatitis

Technically difficult

Increased risk of bleeding

Not widely available

Biopsy of extra-pancreatic site

Bile ducts, major duodenal papilla

80% pancreatic head involvement had IgG4-positive cells on biopsy of the major duodenal papilla

Response to steroidDramatic

Response to steroidRadiographic response seen at 2-3 wks and

normalization at 4-6 wks

Response to steroidSteroid trial controversial

No response within 2 weeks makes IgG4 pancreatitis unlikely

Failed response to steroid Prompt re-evaluation of diagnosisConsider surgery to look for cancer

Making the correct diagnosis is challengingRare diseaseMimic the more common pancreaticobiliary

malignancyNo single diagnostic test available

Price of misdiagnosis is heavyUnnecessary surgery for benign diseaseDelay potentially curative surgery

Japanese Diagnostic Criteria

1. Imaging

- Diffuse/ segmental narrowing of main pancreatic duct

- Diffuse/ localized enlargement of pancreas

2. Serology

- Elevated gamma-globulin, IgG or IgG4 OR

- Presence of autoantibodies eg ANA/ RF

3. Histology

- Lymphoplasmacytic sclerosing pancreatitis

Diagnosis: 1 + 2/3

Take Home MessageIncreasing recognition

Important diagnostic consideration in obstructive jaundice due to pancreatic mass lesion

High index of suspicion

Multidisciplinary collaborationSurgeons/GI

physician/Radiologist/Pathologist

The END