Immunoglobulin G4-associated cholangitis mimicking cholangiocarcinoma in a young boy
RK Miglani, D Murthy, R Bhat, AKV Kumar
Department of Surgical Gastroenterology, Bangalore Medical College and Research Institute, Bangalore, India
R K Miglani
Department of Surgical Gastroenterology, Bangalore Medical College and Research Institute, Bangalore
Autoimmune pancreatitis is a rare form of chronic pancreatitis, which commonly mimics pancreatic carcinoma. Immunoglobulin G4-associated cholangitis (IAC) is a rare type of autoimmune pancreatitis associated with bile duct involvement, which can present with or without pancreatic involvement. Usually, the bile duct involvement is in the form of multiple intra-and extra-hepatic strictures mimicking primary sclerosing cholangitis. Rarely, there can be an isolated stricture which mimics cholangiocarcinoma. Differentiating these from cholangiocarcinoma, though extremely difficult, is of critical importance since it can be treated without surgical intervention. Most cases with rare presentation mimicking cholangiocarcinoma have been reported in elderly patients. We present one such rare presentation of autoimmune pancreatitis in a young 13-year-old patient in whom hepaticojejunostomy was done for a hilar stricture, which later turned out to be related to IAC. To our knowledge this is the first reported case of its kind from India.
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Miglani R K, Murthy D, Bhat R, Kumar A. Immunoglobulin G4-associated cholangitis mimicking cholangiocarcinoma in a young boy.J Postgrad Med 2010;56:140-142
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Miglani R K, Murthy D, Bhat R, Kumar A. Immunoglobulin G4-associated cholangitis mimicking cholangiocarcinoma in a young boy. J Postgrad Med [serial online] 2010 [cited 2020 Jul 10 ];56:140-142
Available from: http://www.jpgmonline.com/text.asp?2010/56/2/140/65294
Autoimmune pancreatitis (AIP) is a rare condition, accounting for 5-8% of chronic pancreatitis cases. It is associated with increased levels of immunoglobulinG (IgG), especially immunoglobulinG4 (IgG4) and the condition is treated with steroids. Presentation as isolated biliary stricture mimicking cholangiocarcinoma is rare. Most cases occur in the older age group and have mainly been reported from the Western countries. This communication reports the condition occurring in a young 13-year-old boy.
A 13-year-old boy presented with progressively increasing jaundice, itching all over the body and occasional episode of pain in the upper abdomen. He did not have fever or weight loss. Examination revealed that the patient was deeply icteric and had mild hepatomegaly. On evaluation by imaging, ultrasound showed dilated intrahepatic biliary radicals (IHBRs) with stricture at common hepatic duct and features of chronic pancreatitis. Magnetic resonance imaging (MRI) [Figure 1] showed a stricture involving the common hepatic duct at the confluence. Atrophic pancreas with foci of calcifications and mild prominence of pancreatic duct were also noted on cross-sectional imaging [Figure 2]. Patient had hyperbilirubinemia and elevated levels of alkaline phosphatase and Carbohydrate Antigen 19-9 (CA19-9) [Table 1].
Suspecting a benign stricture, the patient underwent exploratory laparotomy. At exploration, the common bile duct (CBD), 6 mm in diameter was thickened and was found to be abruptly ending at the hilum. Frozen section from the strictured segment was nonconfirmatory, so resection of CBD with hepaticojejunostomy was done.
Histopathology of the strictured segment showed a dense fibro-collagenous tissue with few interspersed lymphocytes with no evidence of neoplastic tissue [Figure 3].
Based on these findings and in view of the presence of chronic pancreatitis, a diagnosis of AIP with hilar stricture was thought of. The patient's IgG and IgG4 levels were noted to be 2700 mg/dl (620-1400 mg/dl) and 603 mg/dl (et al. in a patient with pancreatitis and hypergammaglobulinemia  This entity is characterized by increased levels of serum gammaglobulin or IgG, specifically IgG4, diffuse enlargement of the pancreas, fibrotic changes around the main pancreatic duct with lymphocytic infiltration, rare presence of pancreatic calcification or pancreatic cysts and occasional association with other autoimmune diseases. Other organs besides the pancreas are often involved in AIP. Their involvement may be diagnosed before, along with or after the diagnosis of AIP. The biliary tract is involved in 60-100% of all patients presenting with AIP.  It has recently been named as Immunoglobulin G4-associated cholangitis (IAC).  IAC affects both intra- and extra-hepatic bile ducts, with the distal CBD being the most common site of involvement.  Biliary imaging may not necessarily reveal this involvement, as it could be noted only on microscopic examination. Histologically, a lympho-plasmacytic infiltrate surrounds the bile ducts in a pattern similar to that seen in the pancreas and IgG4-positive staining of the tissue is often present.  AIP sometimes exhibits stenosis of the lower CBD with dilation of the bile duct upstream. These changes of the biliary tract have been said to be due to chronic pancreatitis. However, in the present case, a band-like stricture of the bile duct presented only in the hilar hepatic region with intrahepatic ductal dilation. Biliary stenosis in our case cannot be explained as being due to chronic pancreatitis. Also, in presence of elevated levels of IgG which came down with steroid therapy indicated that these changes were related to IAC. Patient also had pancreatic calculi, which may be present in AIP in around 5% of cases. However due to the absence of histological proof, presence of associated tropical pancreatitis could not be ruled out. To the best of our knowledge this is the first of its kind of reported case in the adolescent age group in India.
Although pancreatic involvement (such as diffuse pancreatic enlargement or pancreatic mass) is very common in patients with IAC, a few cases have also been described with isolated biliary tract involvement without pancreatic disease.  These strictures may mimic those due to cholangiocarcinoma.
Clinical profile of the IAC has also been described. It usually occurs in older men (85%), presents as obstructive jaundice (77%), is associated with AIP (92%), increased IgG4 levels (74%) and IgG4-positive cells in bile duct biopsy specimens (88%). Serum values of CA 19-9 >100 IU/mL are less likely in IAC compared with cholangiocarcinoma (18% vs. 60%-80%). Surgical resection is associated with a 44% relapse rate, while steroid withdrawal from patients on conservative therapy results in a relapse rate of 53%.  The role of immune-suppressive agents, drugs like azathioprine in maintaining long-term remission is being evaluated. 
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