1356 A Case of IgG4-related Sclerosing Cholangitis Initially Mistaken for Cholangiocarcinoma

Abstract

INTRODUCTION: IgG4 related disease is an orphan immune-mediated fibro-inflammatory disorder histopathologically characterized by lymphoplasmacytic infiltrates, storiform fibrosis and phlebitis with elevated serum IgG4 levels. It has a diverse range of presentation and often mimics malignant, infectious and other inflammatory conditions. We present a case of IgG4 related cholestasis- obstructive typethat was initially worked up for cholangiocarcinoma. CASE DESCRIPTION/METHODS: A 42-year-old male was admitted for right upper quadrant discomfort, dark urine, pale stools and pruritus for 2 weeks. He had lost around 30 pounds in the last 3 months. Physical examination revealed jaundice, submandibular lymphadenopathy and right upper quadrant tenderness. Laboratory findings were total bilirubin of 4.7 mg/dl, direct bilirubin 2.5 mg/dl, alkaline phosphatase (ALP) 733 U/L, gamma-glutamyltransferase 767 U/L, aspartate aminotransferase 240 U/L and alanine aminotransferase of 572 U/L. Computed tomography of the abdomen revealed intrahepatic biliary dilatation, thickened common bile duct, enlargement and hypo-enhancement of the pancreatic body and tail which was confirmed by magnetic resonance cholangiopancreatography (Figure 1). Endoscopic retrograde cholangiopancreatographydemonstratedstricturing in the intrahepatic, common hepatic and common bile ducts, and a stent was implanted. Histopathology of submandibular lymph node biopsy revealed small non-necrotizing granulomas and biliary brushings had no evidence of malignancy with features of acute and chronic inflammation. IgG4 levels were >300 mg/dl. Given the high suspicion for IgG4 related disease, he was treated with prednisone 40 mg daily for 4 weeks. Follow up liver chemistries revealed an ALP of 135 U/L with marked improvement of symptoms. DISCUSSION: IgG4 related autoimmune pancreatitis (AIP) presents as cholestasis- obstructive typedue concomitant sclerosing cholangitis (SC). It is crucial to differentiate this entity from malignancy due to the availability of effective treatments. Although the typical histopathology was absent in our patient on both lymph node and pancreatic needle biopsy, it is important to highlight that fibrosis is rarely seen in lymph nodes and needle biopsy can miss the involved tissue due to its patchy involvement. In summary, we emphasize on the limitations of biopsy and propose treating patients with steroids when the clinical picture if highly suggestive of IgG4 related disease.