Autoimmune pancreatitis and cholangitis

Significantly Elevated CA 19-9 after COVID-19 Vaccination and Literature Review of Non-Cancerous Cases with CA 19-9 > 1000 U/mL

BACKGROUND

CA 19-9 is a commonly assessed tumor marker, considered characteristic of pancreatic ductal adenocarcinoma (PDAC) and biliary tract cancers; however, the positive predictive value of CA 19.9 is too low, and the usage of CA 19.9 as a screening tool in the healthy population remains controversial.

METHODS

The presented case illustrates a reversed diagnosis of highly elevated serum CA 19-9 levels in a 54-year-old female complaining of pain in the epigastric region, shortly after COVID-19 vaccination. Laboratory tests showed a significantly elevated level of the CA 19-9 marker (>12,000 U/mL, reference value: <37 U/mL) with normal pancreatic enzyme activity. The patient underwent imaging examination, which showed no abnormalities, except for increased pancreatic dimension and areas of fluid signal in the pancreas in magnetic resonance imaging (MRI), which may correspond to autoimmune pancreatitis (AIP). The patient remains asymptomatic with a recommendation for a follow-up MRI in 12 months.

RESULTS

A literature review conducted revealed multi-causal CA 19-9 increases above 1000 U/mL, including non-cancerous diseases of the lung, pancreas, liver, ovary, kidney, and others. The median concentration of CA 19-9 regardless of the cause of disease was 2810 U/mL (IQR ± 6895). The median CA 19-9 values in men and women were 3500 (IQR ± 10,050) and 2455 (IQR ± 3927), respectively, and differ significantly between the compared groups (p < 0.05). There was no difference between CA 19-9 values and the categorized cause of the increase.

CONCLUSIONS

Conducting differential diagnosis, it should not be forgotten that most international guidelines recommend the use of CA 19-9 only in conjunction with pathology of pancreas in radiological imaging; however, even such a combination can point the diagnostic pathway in the wrong direction. A highly elevated CA 19-9 level, typically associated with PDAC, may be the result of benign disease including AIP related to COVID-19 vaccination.

Clinical features of IgG4-associated autoimmune pancreatitis and factors related to its recurrence

BACKGROUND

IgG4-associated autoimmune pancreatitis (IgG4-AIP) is a kind of autoimmune-mediated pancreatitis. The clinical manifestations of IgG4-AIP are not specific and the differential diagnosis is often difficult, and the indications and course of glucocorticoid treatment for the disease are still controversial. The aim of this study was to improve the understanding, diagnosis, and treatment of the disease by analyzing the clinical characteristics of the disease, and to reduce the recurrence rate of the disease by analyzing the factors related to its recurrence.

AIM

To investigate the clinical features, therapeutic efficacy, and recurrence of IgG4-AIP.

METHODS

The clinical data of 46 patients with IgG4-AIP were analyzed retrospectively.

RESULTS

The male to female ratio of IgG4-AIP patients was 10.5:1. The most common clinical manifestation was obstructive jaundice. Approximately 52.1% of patients had extrapancreatic organ involvement, with the most commonly affected extrapancreatic organ being the bile duct. The vast majority (91.3%) of patients had higher serum IgG4 levels than normal. The imaging findings were diffuse swelling or local enlargement of the pancreas with stricture of the biliary and pancreatic ducts. The majority (81.2%) of patients underwent pancreatic biopsy under the guidance of endoscopic ultrasonography. Typical pathological findings included fibrous tissue proliferation, lymphocyte and plasma cell infiltration, and acinar atrophy of the pancreas. Half of the patients showed a large number of IgG4 positive plasma cells as revealed by immunohistochemistry. Glucocorticoids were effective for IgG4-AIP, but 36.8% of the patients relapsed after remission, and 71.4% relapsed after stopping glucocorticoids. Logistic regression analysis showed that the risk factors for recurrence were pancreatic portal hypertension and involvement of extra-pancreatic organs. Low-dose glucocorticoid maintenance therapy could prevent recurrence.

CONCLUSION

Due to the lack of specific clinical manifestation, IgG4-AIP is easily misdiagnosed as pancreatic cancer. The main manifestations of IgG4-AIP are increased serum IgG4 level, diffuse or local swelling of pancreas with biliopancreatic duct stricture, multiple organ involvement, IgG4 positive plasma cell infiltration, tissue fibrosis, and response to treatment with glucocorticoids. The risk factors for recurrence of IgG4-AIP are pancreatic portal hypertension and extrapancreatic organ involvement. Low-dose glucocorticoid maintenance therapy can prevent recurrence.

Immunoglobulin G4 associated autoimmune cholangitis and pancreatitis and nivolumab

This letter to editor discussing on the publication on immunoglobulin G4 associated autoimmune cholangitis and pancreatitis following the administration of nivolumab. Concerns on confounding factors are raised and discussed.

Isolated IgG4 Autoimmune Cholangitis in the Absence of Pancreatitis

The IgG4-related disease is an uncommon immune-mediated condition affecting multiple organ systems concomitantly; however, it is very rare for a patient to have isolated IgG4 autoimmune cholangitis or IgG4-related disease confined to the hepatobiliary system. The majority of cases are associated with pancreatitis and are incidentally discovered in the workup of acute or chronic pancreatitis. When it affects the hepatobiliary system, it develops as inflammatory fibrosclerosing cholangitis, which can mimic other hepatobiliary diseases such as primary sclerosing cholangitis. Herein, we present a case of type 1 IgG4 autoimmune cholangitis in the absence of pancreatitis. Our case is particularly unique because type 1 is the most common type associated with autoimmune pancreatitis; however, our patient had type 1 without any evidence of pancreatic involvement. Additionally, like most cases of isolated IgG4 autoimmune cholangitis, our patient was refractory to standard therapy. This case highlights the clinical significance, rarity and severity of isolated IgG4 autoimmune cholangitis.

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.