Biliary Involvement in Type 2 Autoimmune Pancreatitis

Abstract

Autoimmune pancreatitis (AIP) is a rare condition classified in 2 subtypes. Their distinction relies on a combination of clinical, serological, morphological and histological features. Type 1 is a pancreatic manifestation of IgG4-related disease characterized by multiorgan infiltration by IgG4 plasmocytes. In this condition, hepatobiliary infiltration is frequent and often mimics cholangiocarcinoma or primary sclerosing cholangitis. On the other hand, type 2 is commonly limited to the pancreas. Herein, we describe the case of a patient who presented a type 2 AIP associated with cholangiopathy, a condition not described in the established criteria. He first developed a pancreatitis identified as type 2 by the typical histopathological features and lack of IgG4 in the serum and tissue. Despite a good clinical response to steroids, cholestasis persisted, identified by MR cholangiography as a stricture of the left hepatic duct with dilatation of the intrahepatic bile duct in segments 2 and 3. Biliary cytology was negative. Evolution was favorable but after steroid tapering a few months later, the patient suffered from recurrence of the pancreatitis as well as progression of biliary attempt, suspicious for cholangiocarcinoma. As the investigations again ruled out neoplastic infiltration or primary sclerosing cholangitis, azathioprine was initiated with resolution of both pancreatic and biliary attempts.

Keywords: Autoimmune pancreatitis; Biliary involvement.

Fig. 1

Baseline MR imaging. a Axial gadolinium-enhanced T1 image showing signs of acute pancreatitis with an enlargement of the pancreatic tail and a mild stranding of the peripancreatic spaces. b MR cholangiopancreatography showing a stricture of the left hepatic duct with upstream dilatation of the bile ducts of the left hepatic lobe.

Fig. 2

a Overview of one representative SharkCore biopsy showing a slight nonstoriform interlobular fibrosis of the pancreatic tissue, exhibiting a heterogeneous inflammatory infiltrate with predominant neutrophilic accumulation within the interlobular spaces (inset). b Detailed view of the inset in a showing neutrophilic infiltrates (arrowhead) with inconspicuous periacinar lymphoplasmacytic and histiocytic accumulation. c Detailed view of the immunostaining results showing no IgG4-positive plasma cells. This combination of histological and immunostaining findings is highly suggestive for type 2 autoimmune pancreatitis. H&E staining. Original magnification, a ×10, b ×60. IgG4 stain (Cell marque^©, 1: 50). Original magnification, c ×40.

Fig. 3

a The second percutaneous transhepatic cholangiography shows a main stricture (arrow) of the right hepatic duct with upstream dilatation of the bile ducts of the right liver. b Three internal external drainage tube are placed in the right anterior and posterior segments of the right liver and in the left hepatic lobe.

Fig. 4

Control MR imaging. a Axial gadolinium-enhanced T1 image showing diffuse hypotrophy of the pancreas, but without signs of acute pancreatitis. b MR cholangiopancreatography showing a mild dilatation of the intrahepatic bile ducts, but without residual strictures of the main bile ducts.