S1840 The Importance of Cholangioscopic Biopsies: An IgG4-Related Sclerosing Cholangitis Story

Abstract

Introduction: IgG4 related sclerosing cholangitis (IgG4-SC) has generally been associated with autoimmune pancreatitis, retroperitoneal fibrosis, and sialadenitis. However, there are rare cases involving only the biliary tree. In addition, IgG4-SC can be easily confused with cholangiocarcinoma and primary sclerosing cholangitis (PSC). IgG4 serum levels more than 135 suggest IgG4-SC, but lower levels do not rule out the disease. Here, we present an atypical case of IgG4-SC. Case Description/Methods: 68-year-old male with past medical history of alcohol misuse disorder presented for pruritis, scleral icterus, and 40 pounds of weight loss in three weeks. On admission, notable labs were AST 158, ALT 81, ALP 713, total bilirubin 5.8, and direct bilirubin 4.9. IgG was 3203 and IgG4 was 113. Remainder of the work up was negative. Magnetic resonance cholangiopancreatography showed isolated left intrahepatic biliary dilation. Endoscopic retrograde cholangiopancreatography (ERCP) showed segmental strictures at the common hepatic duct and left intrahepatic duct. Cholangioscopy showed a fibrotic intraluminal growth in the upper third of the common bile duct, which was unable to be traversed. Biliary brushings showed only acute inflammation (Figure). A plastic biliary stent was placed for decompression and a percutaneous internal-external biliary drain was performed to facilitate subsequent rendez-vous ERCP. Repeat cholangioscopy showed scarring and fibrosis of the entire biliary tree and segmental stricturing at the hilum and left intrahepatic duct. Cholangioscopy-guided forceps biopsies showed more than ten IgG4 cells per high powered field indicating IgG4-SC. Patient was started on high dose corticosteroids with improvement of his symptoms and lab abnormalities. Discussion: Awareness of IgG4-SC is important as it can mimic cholangiocarcinoma and PSC. Our patient presented with obstructive jaundice and isolated dilatation of the biliary tree with a normal serum IgG4 suggestive of underlying malignancy. However, he also had elevation of total serum IgG, which was suspicious for an underlying autoimmune disorder. Biliary brushings can exclude malignancy but have a poor sensitivity for the diagnosis of IgG4-SC (36%). The most useful modality of diagnosis is cholangioscopy-guided forceps biopsy as this is positive in about 88% of specimens. Thus, IgG4-SC should be considered in patients with an atypical presentation of obstructive jaundice with incongruent lab and imaging findings, as this condition is treatable.Figure 1.: Left picture shows common hepatic duct stricturing and mass on cholangioscopy. Right picture shows left intrahepatic duct stone in light of stricturing on cholangioscopy.