Elsevier

Human Pathology

Volume 39, Issue 10, October 2008, Pages 1548-1551
Human Pathology

Case study
Synchronous autoimmune pancreatitis and infiltrating pancreatic ductal adenocarcinoma: case report and review of the literature

https://doi.org/10.1016/j.humpath.2008.01.021Get rights and content

Summary

An 80-year-old white man underwent pylorus-preserving pancreaticoduodenectomy after presenting with obstructive jaundice and a dilated biliary tree on cholangiopancreatography. Histologic evaluation of the specimen revealed synchronous autoimmune pancreatitis (lymphoplasmacytic sclerosing pancreatitis) and infiltrating ductal adenocarcinoma of the pancreas. The mixed inflammatory infiltrate centered on the pancreatic ducts was associated with acinar loss, parenchymal fibrosis, and obliterative venulitis. Immunohistochemical labeling with an antibody to IgG4 revealed greater than 50 IgG4-positive plasma cells per high power field. Although not appreciated grossly, pancreatic intraepithelial neoplasia-3 and a neurotropic infiltrating poorly differentiated adenocarcinoma of the pancreas were also present. This case highlights the importance of carefully evaluating patients with autoimmune pancreatitis to rule out an underlying neoplasm and the importance of following those who were treated nonsurgically until the disease fully resolves.

Introduction

Autoimmune pancreatitis (AIP), also known as lymphoplasmacytic sclerosing pancreatitis, is a rare form of chronic pancreatitis characterized by a mixed inflammatory infiltrate centered around the pancreatic ducts accompanied by an obliterative venulitis, acinar atrophy, and interstitial fibrosis [1]. Originally described by Sarles et al [2] in 1961 as “primary inflammatory sclerosis of the pancreas,” the term autoimmune pancreatitis was introduced by Yoshida et al [3] in 1995. AIP typically affects middle-aged patients who lack the risk factors associated with chronic pancreatitis [4]. AIP can occur in isolation or in association with other autoimmune diseases including rheumatoid arthritis, Sjögren's syndrome, primary biliary cirrhosis, primary sclerosing cholangitis, and inflammatory bowel disease [4].

The clinical presentation of AIP can vary widely. Most patients present with jaundice or abdominal pain [5]. Radiographically, the classic appearance of AIP on computed tomography (CT) scan consists of diffuse enlargement of the pancreas with effacement of the usual lobular appearance of the pancreas and a low attenuation capsule-like rim [6]. Endoscopic retrograde cholangiopancreatography classically reveals diffuse irregular narrowing of the main pancreatic duct [6]. The hallmark of this disease process is a periductal lymphoplasmacytic infiltrate found on histologic examination of the specimen. Many of the inflammatory cells are plasma cells that express IgG4, and patients with AIP often have elevated serum IgG4 levels (>135 mg/dL) [7].

The clinical presentation and radiographic appearance of AIP can mimic infiltrating pancreatic ductal adenocarcinoma [1], [4]. Traditionally, differentiation from a neoplasm has been made by examination of pathologic specimens after surgical resection [8]. Recently, there have been a growing number of reports of AIP treated with systemic steroids as definitive therapy [9], [10], [11]. These patients were identified through a combination of imaging studies, biopsy specimens, and laboratory abnormalities (elevated serum IgG4 levels). Some investigators have argued that all patients with a pancreatic lesion should undergo serum IgG4 testing and that those with an elevated serum IgG4 level should be initially treated with steroids [9], [11]. These authors argue that patients who respond to steroids can potentially be spared the morbidity associated with pancreatic resection, typically pancreaticoduodenectomy. Here, we report the rare case of a patient with histologically proven synchronous AIP and infiltrating pancreatic ductal adenocarcinoma. This case highlights the need for heightened vigilance when opting to manage AIP patients without surgical resection.

Section snippets

Case report

The patient was an 80-year-old white man in good health who developed obstructive jaundice. CT imaging revealed a dilated biliary tree and a strictured pancreatic duct, without evidence of discrete pancreatic mass. Endoscopic retrograde cholangiopancreatography was unsuccessful in traversing the biliary obstruction, and the patient required a percutaneous transhepatic biliary stent for palliation of his jaundice. The patient underwent a pylorus preserving pancreaticoduodenectomy with an

Pathology findings

Gross inspection of the resected pancreaticoduodenectomy specimen revealed a diffusely enlarged and firm pancreas, with effacement of the overall lobular architecture. The intrapancreatic bile and the main pancreatic ducts were diffusely narrowed. Histologically, the pancreas was remarkable for an intense mixed inflammatory cell infiltrate centered on the pancreatic ducts (Fig. 1A). The inflammatory infiltrate was predominantly composed of lymphocytes and plasma cells, with occasional

Discussion

Because AIP can mimic pancreatic ductal adenocarcinoma and is increasingly diagnosed it can present a diagnostic and management dilemma. Clinicians must try to balance the potential risk of missing the diagnosis of a life-threatening disease against symptom control and the desire to avoid unnecessary surgery. These risks are all the more important in the face of effective treatment of AIP with corticosteroids in many cases.

Several groups have proposed criteria to distinguish AIP from pancreatic

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Cited by (109)

  • Association of IgG4 response and autoimmune pancreatitis with intraductal papillary-mucinous neoplasms

    2017, Pancreatology
    Citation Excerpt :

    The finding by Dhall et al. of varying numbers of IgG4-positive plasma cells in the vicinity of pancreatic ductal adenocarcinomas suggests that these carcinomas may also produce an epitope that elicits an IgG4 response [6]. There are also reports of coincidental occurrence of AIP and pancreatic ductal adenocarcinomas (PDAC) [9–11], and a report of a patient with a mucinous cystic neoplasm and stigmata of AIP [12]. The latter authors speculated that their case reflected “an anti-inflammatory antitumor response driven by Th2 cytokines” rather than a typical type 1 AIP (IgG4-related disease).

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