Autoimmune pancreatitis presenting as obstructive jaundice – A diagnostic challenge

Mansoor C Abdulla; Rooby Erachamveettil Hamza; Jithin S Panicker

doi:10.4103/ghep.ghep_49_21

CASE REPORT

Year : 2022 | Volume : 2 | Issue : 2 | Page : 62-64

Autoimmune pancreatitis presenting as obstructive jaundice – A diagnostic challenge

Mansoor C Abdulla¹, Rooby Erachamveettil Hamza², Jithin S Panicker¹
¹ Department of Internal Medicine, MES Medical College, Perinthalmanna, Kerala, India
² Department of Gastroenterology, MES Medical College, Perinthalmanna, Kerala, India

Date of Submission	31-Dec-2021
Date of Decision	20-Jan-2022
Date of Acceptance	15-Feb-2022
Date of Web Publication	23-Mar-2022

Correspondence Address:
Mansoor C Abdulla
Department of General Medicine, MES Medical College, Perinthalmanna - 679 338, Kerala
India

Source of Support: None, Conflict of Interest: None

DOI: 10.4103/ghep.ghep_49_21

Abstract

Autoimmune pancreatitis (AIP) is a rare form of pancreatitis which can mimic carcinoma head of the pancreas or distal cholangiocarcinoma, causing the diagnostic dilemma. A 64-year-old postmenopausal woman presented with jaundice, generalized itching, and intermittent low-grade fever for 2 weeks. On evaluation, she had a bulky pancreas on imaging and distal biliary stricture on magnetic resonance cholangiopancreatography. She was planned for Whipple's resection, but her serum immunoglobulin G4 (IgG4) was very high. She was started on oral high-dose steroids considering the possibility of AIP and had significant improvement after 2 weeks of treatment. AIP can mimic distal cholangiocarcinoma and can cause a diagnostic challenge in patients admitted with obstructive jaundice. The presence of high serum IgG4 level and treatment response to steroids help in making the diagnosis. This case reminds the readers to consider AIP in patients with obstructive jaundice who have imaging findings of distal cholangiocarcinoma to avoid unnecessary operations on patients without cancer.

Keywords: Autoimmune pancreatitis, distal cholangiocarcinoma, obstructive jaundice

How to cite this article:
Abdulla MC, Hamza RE, Panicker JS. Autoimmune pancreatitis presenting as obstructive jaundice – A diagnostic challenge. Gastroenterol Hepatol Endosc Pract 2022;2:62-4

How to cite this URL:
Abdulla MC, Hamza RE, Panicker JS. Autoimmune pancreatitis presenting as obstructive jaundice – A diagnostic challenge. Gastroenterol Hepatol Endosc Pract [serial online] 2022 [cited 2022 May 24];2:62-4. Available from: http://www.ghepjournal.com/text.asp?2022/2/2/62/340396

Introduction

Autoimmune pancreatitis (AIP) is a form of chronic pancreatitis caused by an autoimmune mechanism. AIP usually presents with jaundice, mild abdominal pain, and weight loss. The clinical presentation of AIP can sometimes mimic other forms of pancreatitis or even pancreatic cancer. AIP is a benign disease that responds well to steroids and does not require surgery. We present a 64-year-old woman who was admitted with obstructive jaundice and pancreatitis, causing a diagnostic dilemma.

Case Report

A 64-year-old woman presented with jaundice, generalized itching, and intermittent low-grade fever for 2 weeks. She was recently detected to have diabetes (1 month back) and was on metformin. She had icterus, and her abdominal examination was normal.

Hemoglobin was 12.0 g/dL; leukocyte count 7,800/μl, platelet count 3, 00,000/μL, and erythrocyte sedimentation rate 39 mm in1 h. Liver function test showed a cholestatic pattern: total bilirubin: 5.3 mg/dL, direct bilirubin: 4.2 mg/dL, alkaline phosphatase: 237 U/L (normal range 20–140 IU/L), gamma-glutamyl transpeptidase: 328 U/L (normal range: 9–48 units per liter), alanine transaminase: 96 U/L, aspartate transaminase: 164 U/L, and normal serum albumin. Serum amylase was 356 U/L (normal range: 23–85 U/L) and lipase was 3090 U/L (normal range: 7–60 U/L). Ultrasonography of the abdomen showed dilated common bile duct with bilobar intrahepatic biliary dilatation and heterogeneously hypoechoic pancreas. There was no periampullary growth on the upper gastrointestinal endoscopy. Contrast-enhanced computed tomography of the abdomen showed intrahepatic biliary dilatation, dilated proximal common bile duct (7 mm) with narrowed mid-distal common bile duct (possibly due to stricture), and bulky pancreas. Magnetic resonance cholangiopancreatography (MRCP) showed bilobar intrahepatic biliary dilatation with dilated proximal common bile duct (9 mm). The dilated common bile duct was traced up to the superior margin of the pancreatic head, but the intrapancreatic portion of the common bile duct appeared diffusely and markedly narrowed with the suggestion of circumferential wall thickening [Figure 1]a. The pancreatic duct was normal. The picture was suggestive of distal cholangiocarcinoma. She was planned for Whipple's resection. Serum immunoglobulin G4 (IgG4) was very high (3.61 g/L-normal level <2.0) and CA 19-9 was normal. Considering the possibility of AIP (high IgG4 level, pancreatitis on imaging, and distal biliary stricture on MRCP), the patient was started on steroids (oral prednisolone 40 mg daily). The patient had significant improvement after 2 weeks of treatment. Repeat liver function test showed total bilirubin: 1.7 mg/dL, alkaline phosphatase: 184 U/L, gamma-glutamyl transpeptidase: 167 U/L, alanine transaminase: 51 U/L, aspartate transaminase: 64 U/L, and serum lipase: 1162 U/L. Repeat MRCP showed no intrahepatic biliary dilatation, reduction in common bile duct dilatation (6.9 mm), and the intrapancreatic portion of the common bile duct was partially visualized (2–3 mm) except for the distal most/periampullary portion [Figure 1]b.

Figure 1: Magnetic resonance cholangiopancreatography showing dilated proximal common bile duct and the intrapancreatic portion of common bile duct showing diffusely and markedly narrowed with the suggestion of circumferential wall thickening (a). Repeat magnetic resonance cholangiopancreatography after treatment showing a reduction in common bile duct dilatation and partial visualization (2–3 mm) of the intrapancreatic portion of the common bile duct (b)

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Discussion

AIP is a form of chronic pancreatitis that often is difficult to distinguish from malignancy of the pancreas and other forms of chronic pancreatitis. Unlike pancreatic malignancies, however, AIP may respond to therapy with corticosteroids and has a strong association with other immune-mediated diseases and increased levels of immunoglobulin subclass 4 (IgG-4).^[1]

The International Consensus Diagnostic Criteria are used for diagnosing AIP, which is based on (1) pancreatic imaging of the parenchyma with computerized tomography scan/magnetic resonance imaging (CT/MRI) or pancreatic ductal imaging with endoscopic retrograde cholangiopancreatography/MRCP, (2) serum IgG-4 levels, (3) other organ involvement, (4) histology of the pancreas, and (5) response to corticosteroid therapy.^[2] Our patient had a high IgG4 level, pancreatitis on imaging, distal biliary stricture on MRCP, and significant treatment response to steroids. The MRCP of the patient was reported by the radiologist as possible distal cholangiocarcinoma and was planned for Whipple's resection. However, considering the possibility of AIP, the patient was started on steroids with which she improved dramatically. AIP, even though uncommon, should be included in the differential diagnosis of obstructive jaundice. When affecting the biliary tract, it may mimic distal cholangiocarcinoma, or it may cause benign mass lesions of the pancreas which can resemble carcinoma head of the pancreas.^[3] The disease predominantly affects elderly men, with the most common presenting symptom being obstructive jaundice. Serum IgG4 has been reported to have a sensitivity of 90% and a specificity of 98%, with an overall accuracy of 95% for differentiating between pancreatic cancer and AIP. Raised IgG4 can be seen in 7%–10% of the patients with pancreatic cancer and approximately 10% of the patients with cholangiocarcinoma.^[4] AIP mimicking distal cholangiocarcinoma was previously reported.^[5],[6]

Conclusion

AIP shows a dramatic response to steroids. AIP can mimic distal cholangiocarcinoma and can cause a diagnostic challenge in patients admitted with obstructive jaundice. The presence of high serum IgG4 levels and treatment response to steroids can help in making a diagnosis. This case reminds the readers to consider AIP in patients with imaging findings of distal cholangiocarcinoma (distal common bile duct stricture) to avoid unnecessary operations on patients without cancer.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given her consent for her images and other clinical information to be reported in the journal. The patient understands that name and initials will not be published, and due efforts will be made to conceal the identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

References

1.	Hamano H, Kawa S, Horiuchi A, Unno H, Furuya N, Akamatsu T, et al. High serum IgG4 concentrations in patients with sclerosing pancreatitis. N Engl J Med 2001;344:732-8.
2.	Shimosegawa T, Chari ST, Frulloni L, Kamisawa T, Kawa S, Mino-Kenudson M, et al. International consensus diagnostic criteria for autoimmune pancreatitis: Guidelines of the International Association of Pancreatology. Pancreas 2011;40:352-8.
3.	Weber SM, Cubukcu-Dimopulo O, Palesty JA, Suriawinata A, Klimstra D, Brennan MF, et al. Lymphoplasmacytic sclerosing pancreatitis: Inflammatory mimic of pancreatic carcinoma. J Gastrointest Surg 2003;7:129-37.
4.	Kawa S, Hamano H. Clinical features of autoimmune pancreatitis. J Gastroenterol 2007;42 Suppl 18:9-14.
5.	Marinho R, Alves A, Pignatelli N, Nunes V. Unclassified autoimmune pancreatitis mimicking pancreatic cancer. J Surg Case Rep 2019;2019:rjy340.
6.	Fanidou D, Filippou N, Katseli A, Papadopoulos G, Skandalakis P, Filippou D. Autoimmune pancreatitis associated with retroperitoneal fibrosis mimicking cholangiocarcinoma. Oxf Med Case Reports 2018;2018:omy056.