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

Prevalence of histological features resembling autoimmune pancreatitis in neoplastic pancreas resections

AIMS

Types 1 and 2 autoimmune pancreatitis (AIP) can mimic pancreatic neoplasia. Due to the small quantity of tissue in mass-targeted pancreas biopsies, inflammatory features may raise the differential of AIP. However, the frequency of AIP-like histology in neoplastic pancreas is not well characterised. Therefore, the specificity of inflammatory lesions on biopsy with respect to the diagnosis of AIP is uncertain.

METHODS AND RESULTS

Neoplastic pancreas resections performed at our institution between 2008 and 2019 were retrospectively reviewed. Features of AIP types 1 and 2 were assessed in the non-neoplastic areas. If features of immunoglobulin (Ig)G4-associated AIP were seen, IgG4 immunohistochemistry was performed. We identified 163 neoplastic pancreas resections. Of these, 34 had one or more types of inflammatory lesions in non-neoplastic pancreatic tissue. Dense lymphoplasmacytic inflammation mimicking type 1 AIP was found in six cases with mild to moderately increased IgG4-positive plasma cells. Neutrophilic infiltrates in small intralobular ducts were found in 20 cases. Mild extralobular ductitis or duct microabscess was found in 10 specimens. Marked neutrophilic duct destruction that resembled granulocytic epithelial lesions was found in 12 cases. Some cases showed multiple features.

CONCLUSION

Approximately 20% of neoplastic pancreas resections showed focal areas that could raise the differential of AIP. More cases showed neutrophilic predominant inflammation as seen in type 2 autoimmune pancreatitis, compared to dense lymphoplasmacytic infiltrates seen in type 1 AIP. Pathologists must be cautious when making a diagnosis of AIP on biopsy tissue based on histological findings alone.

Outcome and Genetic Factors in IgG4-Associated Autoimmune Pancreatitis and Cholangitis: A Single Center Experience

Introduction. Most investigations on autoimmune pancreatitis (AIP) were published on Asian cohorts while those on Caucasians are limited. However, there might be differences related to the origin. Patients and Methods. We analyzed 36 patients and compared type 1 (AIP1) with type 2 (AIP2). Results. The majority of patients suffered from AIP1 (55.6%). AIP1 patients were significantly older than AIP2 patients (54.4 versus 40.8 years). Moreover, 85.0% of AIP1 patients had concurrent autoimmune cholangitis (AIC) while 18.8% of AIP2 patients suffered from overlap to ulcerative colitis (UC). However, AIP1 patients revealed a cholestatic course and had significantly higher immunoglobulin G4 levels (IgG4). When compared to allele frequencies in healthy controls, in patients with AIP1 HLA-B8 reached statistical significance. Response to steroids was excellent in both groups, but we noticed high rates of relapse especially in AIP1 patients. Finally, 3 patients with AIP1 were diagnosed with cholangiocellular carcinoma (CCC). Conclusion. In contrast to Asian studies, we found an almost equal distribution of AIP1 and AIP2 patients in our German cohort. AIP2 patients were younger and mostly of female gender whereas AIP1 patients revealed higher IgG4 levels and involvement of the biliary tract in sense of IgG4-associated cholangitis.

Pathologic Diagnosis of Pancreatic Adenocarcinoma in the United States: Its Status and Prognostic Value

Purpose: Even with the development of new biopsy methods, diagnosis of pancreatic cancer is sometimes without histological evidence. The aim of our study is to find out the status of pancreatic cancer patients who are diagnosed without pathologic confirm and the prognostic value of pathologic diagnosis.

Methods: We identified 52,759 pancreatic adenocarcinoma patients from the Surveillance, Epidemiology, and End Results (SEER) database. Logistic regression model was used to identify factors relating to no pathologic diagnosis. Multivariable Cox regression model identified potential prognostic factors. All statistical tests were two-sided.

Results: There were 6206 (11.76%) patients without pathologic diagnosis. Older age, reported from nursing/convalescent home/hospice or physician's office/private medical practitioner, early year of diagnosis, larger tumor size, pancreatic head cancer, unmarried patients, uninsured and stage I disease all contributed to no pathologic diagnosis. Median cause specific-survival for patients with and without pathologic diagnosis were 7.72 and 3.52 months, respectively. The HR for pathologic diagnosis was 0.92 (95% CI: 0.89-0.95), P<0.001.

Conclusions: Pathologic diagnosis was an independent prognostic factor for pancreatic adenocarcinoma patients. New diagnostic methods are needed to get the pathologic diagnosis.

Utility of serum IgG, IgG4 and carbonic anhydrase II antibodies in distinguishing autoimmune pancreatitis from pancreatic cancer and chronic pancreatitis

PURPOSE

Autoimmune pancreatitis (AIP) can mimic pancreatic cancer in its clinical presentation, imaging features and laboratory parameters. The aim of our study was to compare IgG, IgG4 and anti-CAIIAb serum levels in patients with AIP, pancreatic adenocarcinoma (PA) and chronic pancreatitis (CP) and to assess their clinical significance and utility in differential diagnosis of pancreatic diseases.

PATIENT/METHODS

The study included 124 patients: 45 with PA, 24 with AIP and 55 with CP. Peripheral venous blood samples were obtained from all analyzed patients at the time of hospital admission and total IgG, IgG4 and anti-CAIIAB serum levels were measured using ELISA tests.

RESULTS

Serum levels of IgG, IgG4 and anti-CAIIAb were significantly higher in patients with AIP compared to PA and CP patients (p<0.001). In AIP patients the median IgG levels were 19.7 g/l, IgG4 levels - 301.9 mg/dl and anti-CAIIAb - 81.82 ng/ml, compared to 10.61 g/l, 123.2mg/dl and 28.6 ng/ml, respectively, in PA patients. IgG4 for the cut-off 210 mg/dl showed the best sensitivity and specificity (83.8% and 89.5%) in AIP diagnosis compared to IgG (69.3% and 87.3%, respectively) and anti-CAIIAb (45.3% and 74.3%). However, 16 (35.5%) patients with PA and 14 (25.4%) patients with CP had IgG4 levels greater than 140 mg/dl. Moreover, in 3 (6.67%) patients with pancreatic cancer those values were greater than 280 mg/dl. No patients with CP had IgG4 more than 280 mg/dl.

CONCLUSIONS

IgG4 at cut-off 210 mg/dl showed the best sensitivity and specificity in AIP diagnosis compared to IgG and anti-CAIIAb, however elevations of serum IgG4 may be seen in subjects without AIP, including pancreatic cancer.

Recent advances in research of immunoglobulin G4-related sclerosing cholangitis

Immunoglobulin G4-related sclerosing cholangitis (IgG4-SC) is a recently defined disease entity characterized by elevated serum IgG4, chronic progressive obstructive jaundice, and diffuse or mass-forming inflammatory reaction rich in IgG4-positive plasma cells and lymphocytes associated with fibrosclerosis and obliterative phlebitis, which shares a number of clinical, biochemical, and radiological features with primary sclerosing cholangitis (PSC) or cholangiocarcinoma (CC). IgG4-SC is commonly associated with autoimmune pancreatitis (AIP). Steroid therapy comprises the mainstay of treatment for IgG4-SC patients. However, liver transplantation is the only useful treatment for PSC patients, and CC patients require surgical therapy. Therefore, the accurate discrimination between IgG4-SC and PSC or CC is a very important issue. In this article, we will review the features and role of immunoglobulin G4 (IgG4), the diagnosis and therapy of IgG4-SC, and the relations between IgG4-SC and AIP, PSC or CC.