Endoscopic approach for diagnosing autoimmune pancreatitis

Localized autoimmune pancreatitis mimicking pancreatic cancer: Case report and literature review

Autoimmune pancreatitis (AP) is a rare autoimmune pancreatic manifestation of systemic immunoglobulin G4 (IgG4)-related sclerosing disease. Distinguishing between AP and pancreatic cancer is crucial because the clinical courses, treatments, and prognoses of these two disease entities are quite different. We herein report a case involving a 52-year-old man with subacute epigastralgia who visited our hospital for evaluation of a suspicious pancreatic mass found during esophagogastroduodenoscopy. Enhanced computed tomography (CT) revealed an enlarged lesion in the pancreatic head with encasement of hepatic vessels. The lesion also exhibited increased ¹⁸F-fluorodeoxyglucose accumulation on positron emission tomography/CT imaging, which was highly suggestive of pancreatic cancer. After open biopsy, morphologic examination showed an inflammatory infiltrate in the pancreas, which was compatible with chronic sclerotic pancreatitis. Further laboratory tests revealed an elevated serum IgG4 level, and the diagnosis of sclerotic pancreatitis was then confirmed. After corticosteroid treatment, the pancreatic lesion showed shrinkage on follow-up CT, and the serum IgG4 titer decreased to the normal range. This case suggests that clinicians should be familiar with the clinical presentations and diagnostic criteria of AP versus pancreatic cancer. An awareness of the differences between these diseases may avoid misdiagnosis and unnecessary surgical intervention.

Role of diagnostic and therapeutic endoscopic ultrasonography in benign pancreatic diseases

Standard imaging of pancreas is generally obtained by computed tomography and magnetic resonance imaging. However endoscopic ultrasound (EUS) has become an indispensable tool for the diagnosis of various pancreatic diseases. Because of the close proximity of the EUS probe to the pancreas, EUS provides excellent images of the pancreas. In this review, we discuss the role of EUS in the clinical management of patients with benign pancreatic diseases, i.e., various forms of pancreatitis.

Imaging of focal autoimmune pancreatitis and differentiating it from pancreatic cancer

Autoimmune pancreatitis (AIP) is an inflammatory disorder of pancreas. Two types have been identified: the diffuse and the focal or mass forming. Clinical presentation of AIP overlaps that of pancreatic cancer (PC). Sometimes serum IgG4 and CA 19-9 levels are unable to differentiate AIP from PC. Various series have shown that 5%–21% of resected pancreatic masses for suspected malignancy turned out to be AIP. Accurate diagnosis of focal AIP can avoid unnecessary surgeries. This paper elaborates the various imaging modalities useful in differentiating focal AIP from PC.

Autoimmune pancreatitis mimicking pancreatic cancer

Context:

Autoimmune pancreatitis is a particular type of pancreatitis of presumed autoimmune etiology, it is an entity distinct from all others forms of chronic pancreatitis, characterized by clinical, histopathological, radiographic, serologic and therapeutic features. This benign disease resembles pancreatic carcinoma both clinically and radiographically.

Case Report:

A 27-year-old man presented with obstructive jaundice and evocative image of pancreatic tumor. A pancreaticoduodenectomy (Whipple operation) was performed and pathological examination of the specimen diagnosed AIP. Patient responded well to a course of corticosteroids with resolution of clinical and biological disorders.

Conclusion:

Accurate and timely diagnosis of autoimmune pancreatitis is particularly important because steroid therapy is effective and pancreatic resection is not necessary.

Novel quantitative perfusion analysis with contrast-enhanced harmonic EUS for differentiation of autoimmune pancreatitis from pancreatic carcinoma

OBJECTIVE

Autoimmune pancreatitis (AIP) is often misdiagnosed as pancreatic carcinoma (PC) despite recent advances in imaging tests. The aim of the study was to evaluate whether the quantitative perfusion analysis using software "Time intensity curve" with contrast-enhanced harmonic EUS (CH-EUS) facilitate the differentiation of AIP from PC.

METHODS

Consecutive patients with focal AIP and pancreatic carcinoma who underwent CH-EUS from January 2009 to September 2010 were analyzed. CH-EUS was performed with intravenous administration of an ultrasonographic contrast (Sonazoid) and electronic radial echoendoscope. The graph of time intensity curve (TIC) for pancreatic mass was generated to depict the changes in signal intensity over time within the region of interest (ROI). ROI was placed to cover an area with a pancreatic mass lesion. Based on the analysis of TIC, base intensity before injection (BI), peak intensity (PI), time to peak, and maximum intensity gain (MIG: PI-BI) were calculated.

RESULTS

Eight patients with focal AIP and twenty-two patients with PC were evaluated by TIC. PI and MIG of mass lesion of AIP were significantly higher than that of PC (21.4 dB vs. 9.6 dB, 17.5 vs. 6.6). Receiver operating characteristics analysis yielded an optimal MIG cutoff value of 12.5 with high sensitivity and specificity.

CONCLUSION

Pancreatic mass lesions of AIP and PC exhibited markedly different patterns with the TIC. This novel diagnostic modality using TIC generated by CH-EUS might offer an opportunity to improve accuracy in the differential diagnosis between pancreatic mass lesion of AIP and PC.

Distinguishing autoimmune pancreatitis from pancreaticobiliary cancers: current strategy

OBJECTIVE

A review of the literature to identify current modalities for the diagnosis of autoimmune pancreatitis (AIP) with the objective of establishing a strategy to distinguish it from pancreaticobiliary cancers.

BACKGROUND

Pancreatic and biliary manifestations of AIP mimic pancreaticobiliary cancers. Misdiagnosis of AIP can result in major surgery for a steroid-responsive disease.

METHODS

A review of the literature was performed to identify recent advances in the diagnosis of AIP and evaluate outcomes with various diagnostic strategies to minimize operative intervention for an autoimmune disease.

RESULTS

Diagnostic criteria for AIP are based on histology, imaging, serology, extrapancreatic organ involvement, and response to steroid therapy. The most commonly involved extrapancreatic sites are bile duct, kidney, and retroperitoneum. The Mayo Clinic diagnostic strategy utilizes core biopsy of the pancreas and the Japanese strategy depends on a characteristic pancreatogram. The rate of operative intervention was similar with both strategies and none of the patients with cancer received steroid therapy. Immunoglobulin G subtype 4 (IgG4)-associated cholangitis mimics cholangiocarcinoma and presence of more than 10 IgG4-positive plasma cells/high power field on endoscopic biopsy of the bile duct was diagnostic for AIP in 88% patients. Biliary complications and early relapse are common after surgical resection and immunomodulatory drugs can maintain long-term remission.

CONCLUSION

Criteria based on histology, imaging, endoscopy, serology, extrapancreatic organ involvement, and response to steroid therapy improve the diagnostic yield for AIP. Application of diagnostic and therapeutic protocols by a multidisciplinary team will optimize outcomes with a decline in the rate of operative intervention for AIP, a steroid-responsive disease with propensity for relapse.

The Clinical and Pathological Features of IgG(4)-Related Disease

The rapidly emerging disorder now known as IgG(4)-related disease (IgG(4)-RD) includes a variety of clinical entities once regarded as being entirely separate diseases. Manifestations of IgG(4)-RD have now been reported in essentially all organ systems. Regardless of which organ is involved, tissue biopsies reveal striking histopathological similarities. The hallmark pathology findings are diffuse lymphoplasmacytic infiltrates, abundant IgG(4)-positive plasma cells, modest tissue eosinophilia, and extensive fibrosis. Tumorous swelling and obliterative phlebitis are other frequently observed features. Polyclonal elevations of serum IgG(4) are found in approximately 70% of patients. Many questions pertaining to the etiology, pathophysiology, epidemiology, clinical features, therapy, disease monitoring, and long-term outcomes remain to be addressed. This paper focuses on the clinical and pathological features of IgG(4)-RD.

Autoimmune pancreatitis versus pancreatic cancer: a comprehensive review with emphasis on differential diagnosis

BACKGROUND

Autoimmune pancreatitis (AIP) is a rare form of chronic pancreatitis with a discrete pathophysiology, occasional diagnostic radiological findings, and characteristic histological features. Its etiology and pathogenesis are still under investigation, especially during the last decade. Another aspect of interest is the attempt to establish specific criteria for the differential diagnosis between autoimmune pancreatitis and pancreatic cancer, entities that are frequently indistinguishable.

DATA SOURCES

An extensive search of the PubMed database was performed with emphasis on articles about the differential diagnosis between autoimmune pancreatitis and pancreatic cancer up to the present.

RESULTS

The most interesting outcome of recent research is the theory that autoimmune pancreatitis and its various extra-pancreatic manifestations represent a systemic fibro-inflammatory process called IgG4-related systemic disease. The diagnostic criteria proposed by the Japanese Pancreatic Society, the more expanded HISORt criteria, the new definitions of histological types, and the new guidelines of the International Association of Pancreatology help to establish the diagnosis of the disease types.

CONCLUSION

The valuable help of the proposed criteria for the differential diagnosis between autoimmune pancreatitis and pancreatic cancer may lead to avoidance of pointless surgical treatments and increased patient morbidity.

Endoscopic retrograde cholangiopancreatography for non-gastroenterologists: what you need to know

Endoscopic retrograde cholangiopancreatography (ERCP) represents the most powerful and widely employed platform for pancreaticobiliary interventions. Endoscopic retrograde cholangiopancreatography allows diagnosis and treatment of a broad spectrum of diseases of the pancreaticobiliary tree that are both benign and malignant in nature. Endoscopic retrograde cholangiopancreatography continues to evolve rapidly, and non-gastroenterologists need to understand the indications, contraindications, limitations, and role of ERCP to effectively manage and coordinate the care of patients with known or suspected pancreaticobiliary disease. This article will review the role of ERCP in detail to further an understanding of the procedure as a whole and to assess when referral of a patient for an ERCP or other related test is indicated.