Immunoglobulin G4-Seronegative Autoimmune Cholangiopathy With Pancreatic and Hepatic Involvement Mimicking as Primary Sclerosing Cholangitis

Abstract

Immunoglobulin G4-seronegative autoimmune cholangiopathy is a rare cause of biliary strictures. We describe a 27-year-old man presenting with elevated liver enzymes, recurrent cholangitis/bacteremia, biliary strictures, and normal immunoglobulin G4 levels, who was initially diagnosed with primary sclerosing cholangitis, and later listed for transplantation for recurrent bacteremia. Subsequent surveillance imaging demonstrated morphologic changes consistent with biliary strictures and autoimmune pancreatitis. Initiating corticosteroids resulted in liver enzyme normalization and stricture improvement. Diagnosing seronegative autoimmune cholangiopathy remains challenging given similar presentation to primary sclerosing cholangitis. This case highlights importance of a wide differential for biliary strictures, with increased suspicion in those developing pancreatic changes in this setting.

Keywords: IgG4 cholangiopathy; PSC; autoimmune pancreatitis; biliary strictures; primary sclerosing cholangitis.

Figure 1.

Hematoxylin and eosin (400×)-stained histologic sections of the native liver biopsy demonstrated mild portal inflammation, interlobular bile ducts with lymphocytic cholangitis, portal edema, and ductular reaction compatible with the patient's known diagnosis of primary sclerosing cholangitis (PSC). The presence of lymphocytic cholangitis involving small bile ducts additionally raised suspicion for autoimmune cholangitis or concomitant small duct PSC/exacerbation of PSC.

Figure 2.

Immunohistochemical staining (400×) for immunoglobulin G4 showing a lack of plasma cell infiltrates, further lowering suspicion for autoimmune pancreatitis given absent immunoglobulin G4 markers seen on laboratory testing.

Figure 3.

Both right and left intrahepatic biliary systems were notable for multiple segments of stenosis and dilation (beading) consistent with primary sclerosing cholangitis.

Figure 4.

Left, top: Delayed postcontrast T1-weighted fat-suppressed image demonstrates marked peribiliary thickening and enhancement around the common hepatic duct (green arrow). Left, bottom: Axial T1-weighted precontrast fat-suppressed image reveals sharply demarcated abnormal hypointense T1 signal in the pancreatic tail (blue arrow). Right top: Delayed postcontrast T1-weighted fat-suppressed image obtained 6 months after initiation of steroids demonstrates resolution of peribiliary thickening and enhancement around the common hepatic duct (green arrow). Right, bottom: Delayed postcontrast T1-weighted fat-suppressed image obtained 6 months after initiation of steroids shows normalization of the T1 signal in the pancreatic tail (blue arrow).

Figure 5.

Liver function tests normalize after initiation of corticosteroid therapy in February 2021. AIP, autoimmune pancreatitis; ALT, alanine aminotransferase; AST, aspartate aminotransferase; MRCP, magnetic resonance cholangiopancreatography.