[1679] Isolated Extrahepatic IgG4-Related Sclerosing Cholangitis Mimicking Cholangiocarcinoma

Rondell P Graham, Thomas C Smyrk, Suresh T Chari, Lizhi Zhang. Mayo Clinic, Rochester, MN

Background: Extrahepatic bile ducts are the most commonly involved extrapancreatic site in patients with autoimmune pancreatitis (AIP). IgG4-related sclerosing cholangitis (IgG4-SC) without evidence of pancreatic or other organ involvement is less common and less well recognized. This entity is very difficult to preoperatively distinguish from cholangiocarcinoma. Here we describe 9 cases of isolated IgG4-SC.
Design: We retrospectively identified patients with biliary strictures seen between January 2001 to January 2011 who were clinically suspected to have cholangiocarcinoma, but in whom pathologic assessment showed IgG4-SC. All cases with a previous history of IG4-related disease in another organ (including AIP) were excluded. We examined the clinical, cytologic (including fluorescent in situ hybridization [FISH] results) and radiologic features of these cases. The histologic slides (n=9) were reviewed and appropriate blocks selected for IgG4 immunohistochemistry.
Results: All nine patients were males with a median age of 59 years (range 45 to 76 years). All 9 presented with obstructive jaundice and a cholestatic liver profile and were clinically and radiologically suspected to have cholangiocarcinoma. The strictures involved the common hepatic duct (n=3), common bile duct (n=3) or left and right hepatic ducts (n=3).Serum IgG4 was measured in 8 patients at presentation and was mildly elevated (<2 x of upper limit of normal or 240 mg/dL) in only 3 (38%). Cytology was interpreted as negative in 6 cases, atypical in 1 and suspicious for adenocarcinoma in 1. FISH was positive for aneuploidy of chromosomes 3, 7 and 17 in one case and was equivocal (trisomy 7) in 2. Eight of 9 (89%) patients underwent radical resection for suspected cholangiocarcinoma. Histologic sections revealed a prominent lymphoplasmacytic infiltrate with storiform fibrosis and increased IgG4 positive plasma cells (>30/high power field) in all cases. Obliterative phlebitis was seen in 7 of 8. One patient was diagnosed on biopsy which showed typical morphology of IgG4-SC. On median follow-up of 2.8 years, none of the 9 patients has developed a relapse in any organ.
Conclusions: Extrahepatic IgG4-SC may present as an isolated lesion without evidence of AIP or other organ involvement. The normal serum IgG4 and the absence of other organ involvement, coupled with imaging findings suggestive of cancer and equivocal findings for cancer on cytology and FISH, make surgical resection unavoidable in such patients. Better diagnostic clues for IgG4-SC are needed to avoid major surgery in such patients.
Category: Liver

Monday, March 4, 2013 9:30 AM

Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 259, Monday Morning


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