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

Mass Mimicking Autoimmune Pancreatitis—A Report of Two Cases and Review of Literature

Autoimmune pancreatitis (AIP) consists of two clinically histologically distinct forms (type I and II) of chronic pancreatitis that are histologically different. These forms of AIP classically respond to oral steroids. The focal form of AIP resembles pancreatic carcinoma both clinically and radiologically and it is of utmost importance to make an early correct diagnosis between these two diseases in order to identify the optimal therapeutic strategy and to avoid unnecessary laparotomy or pancreatic resection in AIP patients. Here we report focal forms of type I and II AIP with clinical and imaging features closely mimicking pancreatic carcinoma.

Differential diagnosis between pancreatic involvement in IgG4-related disease and pancreatic cancer

IgG4-related disease is a systemic disorder characterised by diffuse or tumoural inflammatory lesions. It can mimic pancreatic cancer, leading to errors in diagnosis and treatment increasing rates of morbidity and mortality in patients. The aim of this review is to take a differential diagnostic approach to these two entities using epidemiology, clinical and laboratory findings, imaging and histopathology.

Autoimmune pancreatitis masquerading as carcinoma head of pancreas: A case report and review of literature

Introduction

Autoimmune pancreatitis (AIP) is a rare form of chronic inflammatory pancreatic disease secondary to an underlying autoimmune mechanism. It is now considered as pancreatic manifestation of IgG4 related disease, which is a multisystem disease.

Case report

We are reporting a patient who presented with obstructive jaundice and mass head of pancreas on Computed Tomography (CT) scan. Considering a strong clinical suspicion of pancreatic cancer, Whipple procedure was done. Histopathological report revealed intense lymphoplasmacytic infiltrate and fibrosis with collagenisation, so possibility of AIP was suggested. Serum IgG4 levels were advised and found to be increased. Diagnosis of AIP was made and patient responded to steroids.

Discussion

Pre-operative core biopsy of the pancreas and Serum IgG4 levels are sufficient to make the diagnosis and resection is usually not recommended in AIP.

Conclusion

Awareness of the entity and use of ancillary techniques in making the pre-operative diagnosis could have saved the patient from an extensive surgical procedure.

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Autoimmune Pancreatitis is a pancreatic manifestation of IgG4 related disorders.

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It can clinically and radiologically present as pancreatic malignancy.

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Resection is not required in Autoimmune Pancreatitis.

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Pre-operative investigations can save the patient from morbidity due to Whipples.

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Whipples procedure is undesired in these patients.

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This entity should be kept in mind while dealing with mass lesions in head of pancreas.

Serological characteristics of autoimmune pancreatitis and its differential diagnosis from pancreatic cancer by using a combination of carbohydrate antigen 19-9, globulin, eosinophils and hemoglobin

Autoimmune pancreatitis (AIP) is a special type of chronic pancreatitis, which may be misdiagnosed as pancreatic carcinoma. This study aims to verify new biomarkers for AIP and propose a serological pattern to differentiate AIP from pancreatic adenocarcinoma with routinely performed tests. In this study, data of serum samples were collected and compared between 25 patients with AIP and 100 patients with pancreatic carcinoma. Receiver operating characteristic analysis and logistic regression was performed to evaluate the diagnostic effect of serum parameters in differentiating AIP from pancreatic carcinoma alone or in combination. Among several serum markers observed in the two groups, carbohydrate antigen 19-9 (Ca19-9), globulin, eosinophils and hemoglobin were selected as the independent markers. Serum levels of Globulin, Eosinophil percentage in AIP group were significantly higher than in pancreatic cancer group (P<0.05), while hemoglobin and tumor marker CA19-9 levels were lower (P <0.05). The combination of these markers identified patients with AIP with 92% sensitivity and 79% specificity, which indicated relatively high diagnostic value. Elevated serum eosinophils, globulin, together with decreased hemoglobin level can be used as a preoperative indicator for AIP and can help to initiate diagnosis of AIP in time.

Recent advances in research of immunoglobulin G4-related autoimmune pancreatits

Autoimmune pancreatitis (AIP) is a rare type of chronic pancreatitis that belongs to the spectrum of immunoglobulin G4 (IgG4) related diseases. AIP is characterized by lymphoplasmacytic infiltration, storiform fibrosis, obliterative phlebitis, and increased IgG4+ plasma cells. Patients with AIP present clinically with recurrent pancreatitis and obstructive jaundice, symptoms involving bile ducts and salivary glands and so on. Serum IgG4 level is often elevated. The main imaging manifestation of AIP is a "sausage-shaped pancreas" and multiple strictures of the main pancreatic duct. AIP responds sensitively to glucocorticosteroids but relapses easily. In relapsed cases, re-administration of glucocorticosteroids alone or in combination with immune modulators is effective.

The changing faces of IgG4-related disease: Clinical manifestations and pathogenesis

Since the earliest reports in 2001, immunoglobulin G4 (IgG4)-related disease has been defined as an autoimmune systemic disease characterized by the lymphoplasmacytic infiltration of affected tissues leading to fibrosis and obliterative phlebitis along with elevated serum IgG4 levels. Prior to this unifying hypothesis, a plethora of clinical manifestations were considered as separate entities despite the similar laboratory profile. The pathology can be observed in virtually all organs and may thus be a challenging diagnosis, especially when the adequate clinical suspicion is not present or when obtaining a tissue biopsy is not feasible. Nonetheless, the most frequently involved organs are the pancreas and exocrine glands but these may be spared. Immunosuppressants lead to a prompt clinical response in virtually all cases and prevent histological sequelae and, as a consequence, an early differential diagnosis from other conditions, particularly infections and cancer, as well as an early treatment should be pursued. We describe herein two cases in which atypical disease manifestations were observed, i.e., one with recurrent neck lymph node enlargement and proptosis, and one with jaundice. Our understanding of the pathogenesis of IgG4-related disease is largely incomplete but data support a significant role for Th2 cytokines with the contribution of innate immunity factors such as Toll-like receptors, macrophages and basophils. Further, macrophages activated by IL4 overexpress B cell activating factors and contribute to chronic inflammation and the development of fibrosis. We cannot rule out the possibility that the largely variable disease phenotypes reflect different pathogenetic mechanisms and the tissue microenvironment may then contribute to the organ involvement.

Immunoglobulin G4, autoimmune pancreatitis and pancreatic cancer

BACKGROUND

Immunoglobulin G4 (IgG4)-related diseases are a group of diseases characterized by enlargement of the affected organs, elevation of serum IgG4, massive infiltration of affected organs with lymphocytes and plasma cells with IgG4 positivity and tissue fibrosis. Type I autoimmune pancreatitis is one form of IgG4-related disease. For IgG4-related diseases, various localizations are described for up to 10% of malignancies. The aim of our study was to examine IgG4 serum levels and pancreatic tissue with respect to the simultaneous presence of autoimmune pancreatitis in patients with pancreatic cancer.

METHODS

IgG4 serum levels were examined In 106 patients with histologically confirmed pancreatic cancer. The level of 135 mg/dl was considered as the normal value. Pancreatic tissue was histologically examined with respect to the presence of markers of autoimmune pancreatitis.

RESULTS

A higher IgG4 level than the cut-off value of 135 mg/dl was proven in 11 patients with pancreatic cancer. Of these 11 patients, 7 had levels twice the normal limit (65.6%). Autoimmune pancreatitis was diagnosed in these individuals. In the case of 1 patient, it was basically an unexpected finding; another patient was initially diagnosed with autoimmune pancreatitis. Repeated biopsy of the pancreas at the time of diagnosis did not confirm the presence of tumour structures, therefore steroid therapy was started. At a check-up 6 months after starting steroid therapy, the condition of the patient improved subjectively and IgG4 levels decreased. However, endosonographically, malignancy was suspected, which was subsequently confirmed histologically. This patient also demonstrated an IgG4 level twice the normal limit.

CONCLUSION

IgG4-related diseases can be accompanied by the simultaneous occurrence of malignancies, which also applies to autoimmune pancreatitis. Chronic pancreatitis is considered a risk factor for pancreatic cancer. It cannot be reliably confirmed whether this also applies to autoimmune pancreatitis. In accordance with other works, however, it is evident that, despite the described high sensitivity and specificity for IgG4 elevation in the case of autoimmune pancreatitis, even levels twice the normal limit are demonstrable in some individuals with pancreatic cancer, without the presence of autoimmune pancreatitis. We believe that patients with IgG4-related disease, including autoimmune pancreatitis, must be systematically monitored with respect to the potential presence of malignancy.

[Autoimmune pancreatitis mimicking pancreatic tumor]

Autoimmune pancreatitis (AIP) is a rare disease of unknown pathomechanism. AIP belongs to the IgG4-related disease family and responds well to steroids, although the relapse rate can reach up to 20-30%. Differentiation of AIP from the more common pancreatic cancer can be very challenging. About 20% of autoimmune pancreatitis is diagnosed postoperatively during final histological examination. While each of diagnostic investigations provide some additional information towards definitive diagnosis, the question still remains whether it is possible to prevent unnecessary pancreatic resection. We demonstrate the differential diagnostic opportunities when we present our case as well as discuss the literature data of this condition. In conclusion, we think that in case of a focal pancreatic lesion AIP should always be considered.

Autoimmune pancreatitis mimicking pancreatic tumor

Autoimmune pancreatitis (AIP) is a rare disease of unknown pathomechanism. It belongs to the IgG4-related disease family and responds well to steroids, although the relapse rate can reach up to 20–30%. Differentiating AIP from the more common pancreatic cancer can be very challenging. About 20% of AIP is diagnosed postoperatively during final histological examination. Each of the investigative tools can add something to the definitive diagnosis; the question remains whether it is possible to prevent an unnecessary resection. Through our case we would like to demonstrate the differential diagnostic opportunities and present the literary background of this issue. In conclusion, we can state that whenever a focal pancreatic lesion is encountered AIP should always be considered.

Chronic pancreatitis

PURPOSE OF REVIEW

We review important new clinical observations in chronic pancreatitis reported in 2011.

RECENT FINDINGS

Smoking increases the risk of nongallstone acute pancreatitis and the progression of acute pancreatitis to chronic pancreatitis. Binge drinking during Oktoberfest did not associate with increased hospital admissions for acute pancreatitis. The unfolded protein response is an adaptive mechanism to maintain pancreatic health in response to noxious stimuli such as alcohol. Onset of diabetes mellitus in chronic pancreatitis is likely due to progressive disease rather than individual variables. Insufficient pancreatic enzyme dosing is common for treatment of pancreatic steatorrhea; 90 000 United States Pharmacopeia units of lipase should be given with meals. Surgical drainage provides sustained, superior pain relief compared with endoscopic treatment in patients advanced chronic pancreatitis with a dilated main duct ± pancreatic stones. The central acting gabapentoid pregabalin affords a modest 12% pain reduction in patients with chronic pancreatitis but approximately 30% of patients have significant side effects.

SUMMARY

Patients with nongallstone-related acute pancreatitis or chronic pancreatitis of any cause should cease smoking. Results of this year's investigations further elucidated the pancreatic pathobiology due to alcohol, onset of diabetes mellitus in chronic pancreatitis, and the mechanisms and treatment of neuropathic pain in chronic pancreatitis.

Diagnostic Dilemma in a Patient with Jaundice: How to Differentiate between Autoimmune Pancreatitis, Primary Sclerosing Cholangitis and Pancreas Carcinoma

A 68-year-old male patient was referred to our institution in May 2011 for a suspected tumor in the pancreatic head with consecutive jaundice. Using magnetic resonance imaging, further differentiation between chronic inflammation and a malignant process was not possible with certainty. Apart from cholestasis, laboratory studies showed increased values for CA 19-9 to 532 U/ml (normal <37 U/ml) and hypergammaglobulinemia (immunoglobulin G, IgG) of 19.3% (normal 8.0–15.8%) with an elevation of the IgG4 subtype to 2,350 mg/l (normal 52–1,250 mg/l). Endoscopic retrograde cholangiopancreatography revealed a prominent stenosis of the distal ductus hepaticus communis caused by pancreatic head swelling and also a bihilar stenosis of the main hepatic bile ducts. Cytology demonstrated inflammatory cells without evidence of malignancy. Under suspicion of autoimmune pancreatitis with IgG4-associated cholangitis, immunosuppressive therapy with steroids and azathioprine was started. Follow-up endoscopic retrograde cholangiopancreatography after 3 months displayed regressive development of the diverse stenoses. Jaundice had disappeared and blood values had returned to normal ranges. Moreover, no tumor of the pancreatic head was present in the magnetic resonance control images. Due to clinical and radiological similarities but a consecutive completely different prognosis and therapy, it is of fundamental importance to differentiate between pancreatic cancer and autoimmune pancreatitis. Especially, determination of serum IgG4 levels and associated bile duct lesions induced by inflammation should clarify the diagnosis of autoimmune pancreatitis and legitimate immunosuppressive therapy.