A peculiar case of autoimmune pancreatitis and sclerosing cholangitis

A 65-year-old man presented with recurrent abdominal pain and slight weight loss. Computed tomography (CT) and endoscopic ultrasound (EUS) revealed a hypodense, partially cystic mass located in the pancreatic body and tail that raised the suspicion of pancreatic cancer ([Fig. 1]). No distant metastases were detected and the patient underwent surgical resection of the mass and splenectomy, which was complicated by a bleeding splenic artery aneurysm. Surprisingly, only massive inflammation of the pancreas was found on histological examination of the resected specimen.

Fig. 1 Preoperative computed tomography (CT) scan taken 40 seconds after intravenous injection of contrast medium showing a hypodense mass located in the pancreatic body and tail, which is highly suspicious for pancreatic cancer. (Arrow indicates the transition from the pathologic to the normal parenchyma.)

The patient re-presented 1 year later with jaundice for the first time. EUS demonstrated a pseudocyst within the head of the pancreas. Endoscopic retrograde cholangiopancreatography (ERCP) revealed an isolated stenosis of the distal common bile duct ([Fig. 2 a]). This was successfully treated with regularly exchanged endoprotheses, leading to a complete normalization of laboratory parameters.

Fig. 2 Images during endoscopic retrograde cholangiopancreatography (ERCP). a A stenosis of the distal common bile duct is shown 1 year after surgical resection of the pancreatic mass. b A hilar stenosis and several intrahepatic bile duct stenoses (*) are seen 2 years later. c Significant improvement of the stenoses is seen following corticosteroid therapy. (X indicates coils within a splenic artery aneurysm.)

The patient returned 2 years later with fever and jaundice. This time ERCP showed a purulent cholangitis with a stricture of the biliary bifurcation as well as several stenotic intrahepatic bile ducts ([Fig. 2 b]). Brush cytology raised a suspicion of cholangiocarcinoma. Serum IgG4 levels, antinuclear antibody (ANA), antineutrophil cytoplasmic antibody (ANCA), anticarbonic anhydrase II and antilactoferrin antibodies were all within the normal range; however, there was peripheral eosinophilia, which can be associated with autoimmune pancreatitis (AIP) [1]. Histological re-examination of the surgical specimen revealed an impressive lymphoplasmacytic infiltration of the resected pancreas with IgG4-positive cells ([Fig. 3 a, b]). This led finally to the correct diagnosis of AIP type 1 with metachronous autoimmune cholangitis. The patient was treated according to the recently published diagnostic algorithms [2] [3] [4] with long-term, slowly tapered prednisone, with resulting improvement in his clinical symptoms, biliary strictures ([Fig. 2 c]), blood eosinophilia, and laboratory parameters.

Fig. 3 Histological re-examination of the surgical specimen showing: a typical signs of autoimmune pancreatitis including lymphoplasmacytic infiltration with storiform fibrosis (arrows) on hematoxylin and eosin (H&E) staining; b cells that are positive for IgG4 (dark brown staining).

In summary, distinguishing AIP from pancreatic cancer remains a pitfall for clinicians; in some cases, surgical resection remains the treatment of choice because IgG4 levels can be elevated in 10 % of pancreatic cancers [5].

Endoscopy_UCTN_Code_CCL_1AZ_2AG

 

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Competing interests: None

• References

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