Frequent and significant K-ras mutation in the pancreas, the bile duct, and the gallbladder in autoimmune pancreatitis

Maintenance steroid therapy is associated with decreased risk of malignancy and better prognosis of patients with autoimmune pancreatitis: A multicenter cohort study in Japan

BACKGROUND/OBJECTIVES

The association between autoimmune pancreatitis (AIP) and pancreatic cancer (PC) remains controversial. This study aimed to clarify the long-term prognosis and risk of malignancies in AIP patients in Japan.

METHODS

We conducted a multicenter retrospective cohort study on 1364 patients with type 1 AIP from 20 institutions in Japan. We calculated the standardized incidence ratio (SIR) for malignancies compared to that in the general population. We analyzed factors associated with overall survival, pancreatic exocrine insufficiency, diabetes mellitus, and osteoporosis.

RESULTS

The SIR for all malignancies was increased (1.21 [95 % confidence interval: 1.05-1.41]) in patients with AIP. Among all malignancies, the SIR was highest for PC (3.22 [1.99-5.13]) and increased within 2 years and after 5 years of AIP diagnosis. Steroid use for ≥6 months and ≥50 months increased the risk of subsequent development of diabetes mellitus and osteoporosis, respectively. Age ≥65 years at AIP diagnosis (hazard ratio [HR] = 3.73) and the development of malignancies (HR = 2.63), including PC (HR = 7.81), were associated with a poor prognosis, whereas maintenance steroid therapy was associated with a better prognosis (HR = 0.35) in the multivariate analysis. Maintenance steroid therapy was associated with a better prognosis even after propensity score matching for age and sex.

CONCLUSIONS

Patients with AIP are at increased risk of developing malignancy, especially PC. PC is a critical prognostic factor for patients with AIP. Although maintenance steroid therapy negatively impacts diabetes mellitus and osteoporosis, it is associated with decreased cancer risk and improved overall survival.

IgG4-related pancreatobiliary diseases could be associated with onset of pancreatobiliary cancer: A multicenter cohort study

BACKGROUND

The risk and prognosis of pancreatobiliary cancer and in patients with autoimmune pancreatitis (AIP) and IgG4-related sclerosing cholangitis (IgG4-SC) remain unclear. Therefore, we retrospectively investigated the risk of pancreatobiliary cancer and prognosis in patients with AIP and IgG4-SC.

METHODS

Patients with AIP and IgG4-SC at seven centers between 1998 and 2022 were investigated. The following data were evaluated: (1) the number of cancers diagnosed and standardized incidence ratio (SIR) for pancreatobiliary and other cancers during the observational period and (2) prognosis after diagnosis of AIP and IgG4-SC using standardized mortality ratio (SMR).

RESULTS

This study included 201 patients with AIP and IgG4-SC. The mean follow-up period was 5.7 years. Seven cases of pancreatic cancer were diagnosed, and the SIR was 8.11 (95% confidence interval [CI]: 7.29-9.13). Three cases of bile duct cancer were diagnosed, and the SIR was 6.89 (95% CI: 6.20-7.75). The SMR after the diagnosis of AIP and IgG4-SC in cases that developed pancreatobiliary cancer were 4.03 (95% CI: 2.83-6.99).

CONCLUSIONS

Patients with autoimmune pancreatitis and IgG4-SC were associated with a high risk of pancreatic and bile duct cancer. Patients with AIP and IgG4-SC have a worse prognosis when they develop pancreatobiliary cancer.

Current status of type 1 (IgG4-related) autoimmune pancreatitis

In 1995, Yoshida et al. proposed first the concept of "autoimmune pancreatitis" (AIP). Since then, AIP has been accepted as a new pancreatic inflammatory disease and is now divided two subtypes. Type 1 AIP affected immunoglobulin G4 (IgG4) and implicates the pancreatic manifestation of IgG4-related disease, while type 2 is characterized by neutrophil infiltration and granulocytic epithelial lesions (GEL). Recent research has clarified the clinical and pathophysiological aspects of type 1 AIP, which is more than type 2 among the Japanese population. However, many details remain unclear about the pathogenesis and progression of this disease. In this review, we discuss the current knowledge and recent advances relating to type 1 AIP.

Nationwide epidemiological survey of immunoglobulin G4-related disease with malignancy in Japan

BACKGROUND AND AIM

To clarify the clinicoepidemiological characteristics of immunoglobulin G4 (IgG4)-related disease (IgG4-RD) with malignancy, a nationwide epidemiological survey was conducted.

METHODS

Immunoglobulin G4-related disease patients with malignancy who had visited selected hospitals in Japan were surveyed. The study consisted of two stages: the number of IgG4-RD patients with malignancy was estimated by the first questionnaire and their clinicoepidemiological characteristics were assessed by the second questionnaire.

RESULTS

The frequencies of autoimmune pancreatitis (AIP), IgG4-related sialadenitis, IgG4-related eye disease, IgG4-related kidney disease, and IgG4-related retroperitoneal fibrosis were 44.7%, 20.8%, 14.0%, 5.16%, and 5.12%, respectively. The overall prevalence of malignant disease in IgG4-RD cases was estimated to be 10 900 per 100 000 cases, which was significantly higher than that of malignant disease in the general population. The prevalence of malignant lymphoma in IgG4-RD cases was the highest and was estimated to be 1985 per 100 000 cases. IgG4-related kidney disease had the highest frequency of malignant disease (17.1%). In data from 200 patients, 61 (30.5%) cases of cancer were found 2 years or more before the IgG4-RD diagnosis, 92 cases (46%) during the 1 year preceding or following IgG4-RD diagnosis, and 62 cases of cancer (31%) 2 or more years following IgG4-RD diagnosis.

CONCLUSIONS

The nationwide survey for IgG4-RD with malignancy in Japan showed that IgG4-RD may be related with malignant diseases.

Autoimmune Pancreatitis with Gastric Cancer: Some IgG4-related Diseases May Be Paraneoplastic Syndrome

A 70-year-old man was referred to our department for the treatment of early gastric cancer. Contrast-enhanced computed tomography (CT) incidentally showed diffuse enlargement of the pancreas with a capsule-like rim, and blood tests showed elevated serum IgG4 levels, leading to a diagnosis of autoimmune pancreatitis (AIP). Endoscopic treatment for gastric cancer was performed, and pathological findings showed adenocarcinoma with abundant IgG4-positive plasma cell infiltration. Thereafter, the serum IgG4 levels normalized, and the findings of AIP disappeared on CT without steroid treatment. These findings suggest that the gastric cancer activated an IgG4-related immune response, resulting in the development of AIP.

Pancreatic cancer in patients with autoimmune pancreatitis: A scoping review

BACKGROUND

Chronic pancreatitis is a known risk factor of pancreatic cancer (PDAC). A similar association has been suggested but not demonstrated for autoimmune pancreatitis (AIP).

OBJECTIVE

The aim of our study was to identify and analyse all published cases of AIP and PDAC co-occurrence, focusing on the interval between the diagnoses and the cancer site within the pancreas.

METHODS

Relevant studies were identified through automatic searches of the MEDLINE, EMBASE, Scopus, and Web of Science databases, and supplemented by manual checks of reference lists in all retrieved articles. Missing/unpublished data were obtained from the authors of relevant publications in the form of pre-prepared questionnaires.

RESULTS

A total of 45 cases of PDAC in AIP patients were identified, of which 12 were excluded from the analysis due to suspicions of duplicity or lack of sufficient data. Thirty-one patients (94%) had type 1 AIP. Synchronous occurrence of PDAC and AIP was reported in 11 patients (33%), metachronous in 22 patients (67%). In the metachronous group, the median period between diagnoses was 66.5 months (2-186) and a majority of cancers (86%) occurred more than two years after AIP diagnosis. In most patients (70%), the cancer originated in the part of the pancreas affected by AIP.

CONCLUSIONS

In the literature, there are reports on numerous cases of PDAC in AIP patients. PDAC is more frequent in AIP type 1 patients, typically metachronous in character, and generally found in the part of the pancreas affected by AIP.

Autoimmune pancreatitis and pancreatic cancer: Epidemiological aspects and immunological considerations

Ordinary chronic pancreatitis is a well-known risk factor for pancreatic cancer, whereas such an association with autoimmune pancreatitis (AIP) is widely debated. Due to the rarity of the latter disorder, there are few specific clinical and epidemiological studies investigating the relation between AIP and pancreatic cancer, which do not seem to support it. However, these studies are affected by several limitations and, therefore, a link between AIP (and, specifically, type 1 AIP) and pancreatic cancer cannot be ruled out definitively on this basis. Moreover, several immunopathological aspects of type 1 AIP and, in general, immunoglobulin G4-related disease can create an immunological context that may impair the tumoral immunosurveillance and promote the pancreatic carcinogenesis and its progression. In detail, Th2 immunological dominance, type 2 macrophage polarization and basophil infiltration observed in type 1 AIP, may play a permissive role in creating a favorable immunological environment for pancreatic carcinogenesis, in addition to the immunosuppressive therapies that can be used in these patients.

Systemic IgG4-Related Disease Masquerading as Cholangiocarcinoma: A Case Report Underscoring the Importance of Medical History

BACKGROUND Immunoglobulin (Ig) G4-related disease is a rare disease of unknown pathophysiology, which can affect multiple organs leading to tissue fibrosis and organ failure. The present case report describes a patient with systemic IgG4-related disease (IgG4-RD) that occurred over a 1-year period and affected multiple organs at different times. Imaging studies, interventional procedures, changes in laboratory parameters, and histopathology demonstrate the novel and known aspects of this disease before and during prednisolone monotherapy and in combination with azathioprine. CASE REPORT A 64-year-old man presented with weight loss and painless jaundice, which was highly suspicious for cholangiocarcinoma. A thorough medical history together with laboratory tests, imaging procedures, and endoscopic interventions confirmed that surgery was not needed and led to the final diagnosis of histologically-confirmed, IgG4-related sclerosing cholangitis and autoimmune pancreatitis type 1. Other typical organ manifestations of systemic IgG4-RD were diagnosed through a thorough medical review, which led to immunohistochemical reevaluation of past surgical specimens. Besides the IgG4-related organ manifestations, which can include periorbital xanthelasmas, our patient developed a pulmonary adenocarcinoma 6 years after the initial clinical onset of IgG4-RD. After immunosuppressive treatment with prednisolone alone and subsequently in combination with azathioprine, the patient's IgG4-RD resolved. CONCLUSIONS Interdisciplinary collaboration is required to diagnose IgG4-RD that involves multiple organs. Patient medical history remains crucial for diagnosis and attention should be paid to avoiding unnecessary surgery. Tumors (lung adenocarcinomas) and xanthelasmas can develop because of IgG4-RD. Glucocorticoids and additional azathioprine may be advisable for maintenance treatment.

IgG4-related sclerosing cholangitis may be a risk factor for cancer

BACKGROUND/PURPOSE

The relationship between autoimmune pancreatitis (AIP) and malignancy has been reported. However, the potential risk for cancer in patients with immunoglobulin 4 (IgG4)-related sclerosing cholangitis (IgG4-SC) is unclear. The present study aimed to evaluate the incidence of cancer in IgG4-SC patients.

METHODS

We retrospectively collected clinical data for 121 patients diagnosed with IgG4-SC from 7 hospitals. We calculated the standardized incidence ratio (SIR) of cancer in IgG4-SC patients based on the national cancer rates. The SIR of the period after the diagnosis of IgG4-SC were calculated.

RESULTS

The mean follow-up period was 6.4 years, with 121 IgG4-SC patients. During the follow-up period, 26 patients had cancer, and 29 cancers were diagnosed. The SIR of cancer after the diagnosis of IgG4-SC was 1.90 (95% confidence interval [CI] 1.67-2.21). The SIR of pancreatic and bile duct cancer was 10.30 and 8.88, respectively. The SIR of cancer in <1 year, 1-5 years, and >5 years after diagnosis of IgG4-SC were 2.58, 1.01, and 2.44, respectively.

CONCLUSIONS

IgG4-SC patients have a high risk of cancer including pancreatic and bile duct cancer. The risk of cancer was high less <1 year and >5 years after diagnosis of IgG4-SC. Therefore, IgG4-SC patients may require careful long-term follow-up.

Autoimmune Pancreatitis after a Seven-Year History of Suspicious Pancreatic Cancer

In this case report, we present a case of autoimmune pancreatitis (AIP) diagnosis in a patient after a 7-year history of suspicious pancreatic cancer. Kim's and Japanese criteria were used to diagnose AIP. Our case avoided undesirable invasive procedures and recovered thanks to the proper diagnosis and timely treatment with prednisone. Early and accurate diagnosis of AIP, in this case, had a significant impact on the treatment and prognosis process.

Cholangiocarcinoma Presenting after Eight Years of Treatment of IgG4-Related Autoimmune Pancreatitis with Steroids

Autoimmune pancreatitis (AIP) is characterized by pancreatic manifestations of IgG4-related disease. Malignancies in patients with AIP have been reported, but carcinoma of the bile duct is extremely rare. We report a patient with IgG4-related AIP who developed cholangiocarcinoma after 8 years of steroid treatment. A 76-year-old male presented with fever (37.8°C) due to biliary obstruction and cholangitis. He had been treated with steroids for 8 years to control inflammation due to IgG4-related AIP. During 8 years of treatment, hepatobiliary enzyme levels were well controlled within their normal range, but serum IgG4 levels remained elevated. A computed tomography scan showed intrahepatic bile duct dilatation. Magnetic resonance cholangiopancreatography showed obstructive changes at the junction of the cystic and common ducts. To relieve biliary obstruction, endoscopic bile duct drainage using a nasobiliary tube was performed, and cytology was Class IV. Aorto-caval lymph node enlargement was found at laparotomy, intraoperatively diagnosed as adenocarcinoma, and resection was abandoned. He died 4 months postoperatively. We report a patient with IgG4-related AIP complicated by cholangiocarcinoma which developed after 8 years of steroid treatment. Even if hepatobiliary markers are well controlled, periodic follow-up with imaging studies may facilitate detection of an early cholangiocarcinoma.

The long-term outcomes of patients with immunoglobulin G4-related sclerosing cholangitis: the Mayo Clinic experience

BACKGROUND

The long-term outcomes of immunoglobulin G4-related sclerosing cholangitis (IgG4-SC) are not well known.

METHODS

The outcomes of patients with IgG4-SC at Mayo Clinic (1999-2018) were compared to an age- and gender-matched (1:1 ratio) group of patients with primary sclerosing cholangitis (PSC).

RESULTS

We identified 89 patients with IgG4-SC; median age at diagnosis was 67 years, 81% were males, and the median follow-up was 5.7 years. Seventy-eight patients received prednisone for induction of remission, and 53 received at least one other immunosuppressive agent for maintenance of remission. Of the IgG4-SC group, 10 died (median time from diagnosis until death was 6.5 years): 2 due to cirrhosis, 3 due to cholangiocarcinoma (CCA), and 5 due to non-hepatobiliary causes. Eleven patients in the PSC group underwent liver transplantation, while none did in the IgG4-SC group. The incidence of a hepatobiliary adverse event (cirrhosis or CCA) was 3.4 times greater in the PSC compared to the IgG4-SC group (events per 1000 person-years: 52.6; 95% CI 38-73; vs. 15.6; 95% CI 7-32). The probability of development of a hepatobiliary adverse event within 10 years was 11% in the IgG4-SC compared to 45% in the PSC group (P = 0.0001). The overall survival tended to be higher in the IgG4-SC compared to the PSC group (10-year: 79% vs. 68%, respectively; P = 0.11).

CONCLUSIONS

In a cohort of IgG4-SC patients, 88% of whom were treated with immunosuppressive drugs, the risk of cirrhosis and CCA was significantly lower compared to an age- and gender-matched group with PSC.

Management of biliary stricture in patients with IgG4-related sclerosing cholangitis

Background

We aimed to determine the optimal approach with endoscopic biliary drainage (EBD) and corticosteroid (CS) for the treatment of IgG4-related sclerosing cholangitis (ISC).

Methods

To evaluate the safety of EBD for treatment of biliary stricture caused by ISC, we assessed the risk of stent dislodgement and sought to determine the most appropriate time for stent removal. We also assessed the safety of treatment with CS alone for patients with obstructive jaundice, and the rate of and risk factors for biliary tract complications.

Results

Sixty-nine patients with ISC treated with CS were enrolled. Twenty-eight patients (40.6%) were treated with EBD for biliary stricture before CS initiation. Intentional stent removal was performed in thirteen (46.4%) after confirming CS-induced improvement. Eleven of thirteen patients (84.6%) underwent stent removal within 1 month after CS initiation and all their stent removals were safely carried out without early (within two weeks) recurrence of obstructive jaundice. Ten of twenty-eight patients (35.7%) experienced spontaneous stent dislodgement after CS initiation, and seven (70%) of them developed stent dislodgement two weeks to two months after CS initiation. Among forty-one patients treated with CS alone without EBD, 10 patients had obstructive jaundice at the time of CS initiation and all of them achieved clinical improvement without biliary tract infection. During the follow-up, three patients (4.3%), all of whom had undergone EBD, developed bile-duct stones, while none of those treated with CS alone developed bile-duct stones (p = 0.032). Long-term biliary stenting was a risk factor for bile-duct stones.

Conclusions

Biliary stent removal should be carried out within 2 weeks after CS initiation if biliary stricture improves to prevent stent dislodgement. Obstructive jaundice can be treated safely with CS alone in patients without infection. Clinicians should be aware of the possibility of bile-duct stones in patients treated with EBD.

Autoimmune Pancreatitis and IgG4-Related Disease: The Storiform Discovery to Treatment

Autoimmune pancreatitis (AIP) is an entity that has been recognized since 1961. Prior to the discovery of elevated serum IgG4 as a useful biomarker for its diagnosis, Dr. Yoshida in 1995 first described the entity of AIP, which in retrospect closely resembles the current concept of type 1 AIP. Since the discovery of IgG4 as a biomarker (the IgG4-era), a novel concept of IgG4-related disease (IgG4-RD) has been accepted as being comprised of two subtypes of AIP: type 1 defined as the pancreatic manifestation of IgG4-RD, and type 2 characterized by granulocytic epithelial lesions. The characteristic features of type 1 AIP are increased serum IgG4 levels, lymphoplasmacytic sclerosing pancreatitis (abundant infiltration of IgG4+ plasmocytes and lymphocytes, storiform fibrosis, and obliterative phlebitis), extrapancreatic manifestations of IgG4-RD (e.g., sclerosing cholangitis, sclerosing sialadenitis, retroperitoneal fibrosis), and steroid responsiveness. These entities can be differentiated from mimickers by a combination of serum IgG4 level, imaging features, and histopathological findings. The current first-line therapy is corticosteroids, or rituximab in high-risk patients with steroid intolerance. Although relapse rates are high, treatment of relapsed disease remains experimental.

A Diagnostically Challenging Case of Autoimmune Pancreatitis Due to Contamination of the Pathological Specimen with Early Gastric Cancer

A 73-year-old man with worsened diabetes underwent abdominal computed tomography and was diagnosed with localized enlargement of the pancreatic tail. Based on the suspicion of autoimmune pancreatitis, endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) was performed. A cytologic examination showed findings suggestive of adenocarcinoma. Due to discrepancies between the imaging and pathological findings, esophagogastroduodenoscopy was performed. An extensive early gastric cancer lesion was detected in the posterior wall of the gastric corpus. It was therefore likely that puncturing through the tumor resulted in the contamination with cancer tissue. The possibility of a concomitant malignancy should be considered in EUS-FNA, and thorough examinations should be conducted.

Up-regulation of activation-induced cytidine deaminase and its strong expression in extra-germinal centres in IgG4-related disease

Immunoglobulin (Ig) G4-related disease (IgG4-RD) is a systemic disorder involving benign mass formation due to fibrosis and intense lymphoplasmacytosis; the chronic inflammation associated with the disease might also contribute to oncogenesis. Activation-induced cytidine deaminase (AID), normally expressed in germinal centre activated B-cells, is an enzyme that edits DNA/RNA and induces somatic hypermutation and Ig class switching. AID expression is strictly controlled under physiological conditions; however, chronic inflammation and some infectious agents induce its up-regulation. AID is overexpressed in various cancers and may be important in chronic inflammation-associated oncogenesis. We examined AID expression in IgG4-related sialadenitis (n = 14), sialolithiasis (non-specific inflammation, n = 13), and normal submandibular glands (n = 13) using immunohistochemistry and quantitative real-time polymerase chain reaction (qPCR). Immunohistochemistry revealed significantly more AID-expressing cells in IgG4-related sialadenitis than in sialolithiasis or normal submandibular gland samples (P = 0.02 and P < 0.01, respectively); qPCR yielded similar results. Thus, AID was significantly more up-regulated and had higher expression in extra-germinal centres in IgG4-RD than in non-specific inflammation or normal conditions. This report suggests that IgG4-RD has several specific causes of AID up-regulation in addition to inflammation. Furthermore, chronic inflammation-associated AID-mediated oncogenesis is possible in IgG4-RD.

KRAS fluorescence in situ hybridisation testing for the detection and diagnosis of pancreatic adenocarcinoma

AIMS

The aim of our study was to analyse correlations between KRAS mutation status, chromosomal changes that affect KRAS status in cells from pancreatic tumours.

METHODS

We collected 69 cases of surgically resected pancreatic ductal adenocarcinoma (PDA) and seven cases of chronic pancreatitis (CP). Chromosomal abnormalities of KRAS and CEP12 were detected using fluorescence in situ hybridisation (FISH).

RESULTS

The number of CEP12 signals per cell ranged from 1.78 to 2.04 and 1.46 to 4.88 in CP and PDA samples, respectively, while the number of KRAS signals per cell ranged from 1.94 to 2.06 and 1.88 to 8.18 in CP and PDA samples, respectively. The 'chromosomal instability index', which was defined as the percentage of cells with any chromosomal abnormality, was over 5.7 times greater in PDA than in CP. We performed KRAS mutation analysis by direct sequencing and found that tumours with KRAS mutations have a significantly higher mean KRAS signal per cell from PDA samples compared with tumours with wild-type KRAS. KRAS amplification was noted in 10% of cases. Although we found that lymph node metastasis and distal metastasis of PDA were more frequent in cases with KRAS amplification, this was not correlated with overall survival. Using a threshold of 40%, we found that the chromosomal instability index robustly discriminated PDA cells from CP cells.

CONCLUSIONS

Based on these findings, we concluded that FISH testing of KRAS using cytology samples may represent an accurate approach for the diagnosis of PDA.

Promoter hypomethylation of SKI in autoimmune pancreatitis

The relationship between methylation abnormality and autoimmune pancreatitis (AIP)-a representative IgG4-related disease-has not yet been elucidated. We identified SKI might have a significant methylation abnormality in AIP through methylation array analysis using the Illumina Infinium Human Methylation 450K BeadChip array, and investigated the relationship of SKI with AIP clinicopathological features. The methylation rate of SKI was assessed by quantitative SYBR green methylation-specific PCR, and the degree of SKI expression in tissue specimens was assessed by immunohistochemistry in 10 AIP cases, 14 cases of obstructive pancreatitis area in pancreatic ductal adenocarcinoma (PDA) without a history of AIP, and 9 normal pancreas (NP) cases. The SKI methylation ratio was significantly lower in AIP than in PDA and NP. Additionally, the immunohistochemical staining-index (SI) score for SKI was significantly higher in AIP than NP, although there was no significant difference between AIP and PDA. There was a strong negative correlation between SI score and SKI methylation ratio, and between the serum concentrations of IgG4 and the SKI methylation ratio. There was a moderate positive correlation between the serum concentrations of IgG4 and SI. SKI is thought to be an oncogene indicating that SKI hypomethylation and carcinogenesis might be linked to AIP. Furthermore, the correlation between serum concentrations of IgG4 and SKI methylation levels suggest SKI might be involved in the pathogenesis of AIP. However, the role of SKI has not been clearly elucidated. Further studies are needed to understand further the function of SKI.

Current perspectives on autoimmune pancreatitis and IgG4-related disease

IgG4-related disease (IgG4-RD) is a fibroinflammatory disorder recognized as a novel clinical entity with either synchronous or metachronous multi-organ involvement. Patients with IgG4-RD show diffuse or focal organ enlargement and mass-forming or nodular/thickened lesions with abundant infiltration of IgG4-positive plasmacytes and fibrosis, and such patients respond well to steroid treatment. It should be differentiated from mimics by a combination of serum IgG4 level, imaging features, and histopathological findings. The current first-line drug is corticosteroids, or rituximab in high-risk patients for steroid intolerance. Although relapse rates are high, standardized protocols for relapsed cases have not been approved yet. Based on genetic factors, disease-specific or -related antigens, abnormal innate and adaptive immunity may be involved, although the precise pathogenic mechanism and long-term outcome still remain unclear.

Methylation of Tumor Suppressor Genes in Autoimmune Pancreatitis

OBJECTIVES

Autoimmune pancreatitis (AIP) is a representative IgG4-related and inflammatory disease of unknown etiology. To clarify mechanisms of carcinogenesis resulting from AIP, we focused on methylation abnormalities and KRAS mutations in AIP.

METHODS

Six tumor suppressor genes (NPTX2, Cyclin D2, FOXE1, TFPI2, ppENK, and p16) that exhibited hypermethylation in pancreatic carcinoma were selected for quantitative SYBR green methylation-specific polymerase chain reaction in 10 AIP specimens, 10 pancreatic adenocarcinoma cases without history of AIP containing carcinoma areas (CAs) and noncarcinoma areas (NCAs), and 11 normal pancreas (NP) samples. KRAS mutation in codons 12, 13, and 61 were also investigated using direct sequencing.

RESULTS

Hypermethylation events (≥10%) were identified in NPTX2, Cyclin D2, FOXE1, TFPI2, ppENK, and p16 in 1, 2, 2, 0, 2, and 0 CA cases, respectively, but not in these 6 candidate genes in AIP, NCA, and NP. However, the TFPI2 methylation ratio was significantly higher in AIP than NCA and NP. Direct sequencing results for KRAS showed no single-point mutations in AIP.

CONCLUSIONS

These are the first studies characterizing methylation abnormalities in AIP. AIP's inflammatory condition may be related to carcinogenesis. Further study will elucidate methylation abnormalities associated with carcinogenesis in AIP.

Simultaneous occurrence of autoimmune pancreatitis and pancreatic cancer in patients resected for focal pancreatic mass

AIM

To assess the occurrence of autoimmune pancreatitis (AIP) in pancreatic resections performed for focal pancreatic enlargement.

METHODS

We performed a retrospective analysis of medical records of all patients who underwent pancreatic resection for a focal pancreatic enlargement at our tertiary center from January 2000 to July 2013. The indication for surgery was suspicion of a tumor based on clinical presentation, imaging findings and laboratory evaluations. The diagnosis of AIP was based on histology findings. An experienced pathologist specialized in pancreatic disease reviewed all the cases and confirmed the diagnosis in pancreatic resection specimens suggestive of AIP. The histological diagnosis of AIP was set according to the international consensus diagnostic criteria.

RESULTS

Two hundred ninety-five pancreatic resections were performed in 201 men and 94 women. AIP was diagnosed in 15 patients (5.1%, 12 men and 3 women) based on histology of the resected specimen. Six of them had AIP type 1, nine were diagnosed with AIP type 2. Pancreatic adenocarcinoma (PC) was also present in six patients with AIP (40%), all six were men. Patients with AIP + PC were significantly older (60.5 vs 49 years of age, P = 0.045), more likely to have been recently diagnosed with diabetes (67% vs 11%, P = 0.09), and had experienced greater weight loss (15.5 kg vs 8.5 kg, P = 0.03) than AIP patients without PC. AIP was not diagnosed in any patients prior to surgery; however, the diagnostic algorithm was not fully completed in every case.

CONCLUSION

The possible co-occurrence of PC and AIP suggests that preoperative diagnosis of AIP does not rule out simultaneous presence of PC.

Randomised controlled trial of long-term maintenance corticosteroid therapy in patients with autoimmune pancreatitis

OBJECTIVE

Corticosteroid has been established as the standard therapy for autoimmune pancreatitis (AIP), but the requirement for maintenance corticosteroid therapy is controversial. We conducted a randomised controlled trial to clarify the efficacy of maintenance corticosteroid therapy in patients with AIP.

DESIGN

We conducted a multicentre, tertiary setting, randomised controlled trial. After the induction of remission with the initial oral prednisolone (PSL) treatment, maintenance therapy with PSL at 5-7.5 mg/day was continued for 3 years or withdrawn at 26 weeks. The primary endpoint was relapse-free survival over 3 years and the secondary endpoint was serious corticosteroid-related complications. All analyses were performed on an intention-to-treat basis.

RESULTS

Between April 2009 and March 2012, 49 patients with AIP were randomly assigned to the maintenance therapy group (n=30) or the cessation group (n=19). Baseline characteristics were not different between the two groups. Relapses occurred within 3 years in 11 out of 19 (57.9%) patients assigned to the cessation group, and in 7 of 30 (23.3%) patients in the maintenance therapy group. The relapse rate over 3 years was significantly lower in the maintenance therapy group than that in the cessation group (p=0.011). The relapse-free survival was significantly longer in the maintenance therapy group than that in the cessation group (p=0.007). No serious corticosteroid-related complications requiring discontinuation of PSL were observed.

CONCLUSIONS

Maintenance corticosteroid therapy for 3 years may decrease relapses in patients with AIP compared with those who discontinued the therapy at 26 weeks.

TRIAL REGISTRATION NUMBER

UMIN000001818; Results.

Intraductal Papillary Neoplasm of the Bile Duct With Invasive Adenocarcinoma Complicating IgG4-related Sclerosing Cholangitis: Report of a Case

Although there have been many previous studies of IgG4-related SC focusing on the differential diagnosis from cholangiocarcinoma, only a few patients with cholangiocarcinoma against a background of IgG4-related SC have been reported. We herein present a case of intraductal papillary neoplasm of the bile duct (IPNB) associated with invasive carcinoma complicating IgG4-related sclerosing cholangitis. A 71-year-old female with icterus was admitted to a local hospital, where stricture of the extrahepatic bile duct were detected, and subsequently referred to our hospital for possible surgery. Abdominal multidetector-row computed tomography demonstrated marked wall thickening along the entire extrahepatic bile duct. The left lateral superior bile duct (B2) and left lateral inferior duct (B3) were individually obstructed, and percutaneous transhepatic biliary drainage catheters were placed in B2 and B3 separately. The patient was diagnosed to have diffusely spread cholangiocarcinoma and underwent right hepatic trisectionectomy with caudate lobectomy and pancreatoduodenectomy. A histological examination revealed intraductal papillary tumors composed of fibrovascular stalks covered by neoplastic epithelium. Carcinomatous invasion of the papillary tumors was observed in the fibromuscular layer, and there was abundant infiltration of inflammatory cells with fibrosis outside of the cancerous tissue. The inflammatory cells were primarily composed of plasma cells, a majority of which were positive for IgG4 (&gt;30 cells/high-power field); the postoperative serum IgG4 level was 890 mg/dL. Therefore, a diagnosis of coexisting IPNB associated with invasive carcinoma and IgG4-related sclerosing cholangitis was made. To the best of our knowledge, this is the first report of IPNB complicating IgG4-related sclerosing cholangitis.

Targeted next-generation sequencing of FNA-derived DNA in pancreatic cancer

To improve the diagnostic value of fine-needle aspiration (FNA)-derived material, we perform targeted next-generation sequencing (NGS) in patients with a suspect lesion of the pancreas. The NGS analysis can lead to a change in the treatment plan or supports inconclusive or uncertain cytology results. We describe the advantages of NGS using one particular patient with a recurrent pancreatic lesion 7 years after resection of a pancreatic ductal adenocarcinoma (PDAC). Our NGS analysis revealed the presence of a presumed second primary cancer in the pancreatic remnant, which led to a change in treatment: resection with curative intend instead of palliation. Additionally, NGS identified an unexpected germline CDKN2A 19-base pair deletion, which predisposed the patient to developing PDAC. Preoperative NGS analysis of FNA-derived DNA can help identify patients at risk for developing PDAC and define future therapeutic options.

Long-term outcomes of autoimmune pancreatitis

Autoimmune pancreatitis (AIP) has been considered a favorable-prognosis disease; however, currently, there is limited information on natural course of AIP during long-term follow-up. Recently published studies regarding the long-term outcomes of AIP has demonstrated the developments of pancreatic stone formation, exocrine insufficiency, and endocrine insufficiency are observed in 5%-41%, 34%-82%, and 38%-57% of patients having the disease. Furthermore, the incidence rate of developing pancreatic cancer ranges from 0% to 4.8% during the long-term follow-up. The event of death from AIP-related complications other than accompanying cancer is likely to be rare. During follow-up of AIP patients, careful surveillance for not only relapse of the disease but also development of complications at regular intervals is needed.

A case of autoimmune pancreatitis effectively treated with an immunosuppressant (azathioprine)

The patient was a 42-year-old man who presented at our hospital with obstructive jaundice. Although antinuclear antibody test results were negative, and immunoglobulin G4 (IgG4) was not elevated, endoscopic ultrasound revealed a mixed internal hyperechoic and diffuse hypoechoic pattern, a finding consistent with autoimmune pancreatitis. Endoscopic retrograde cholangiopancreatography further revealed irregular narrowing of the main pancreatic duct and sclerosing cholangitis with distal biliary stricture. In addition, endoscopic ultrasound with fine needle aspiration cytology resulted in a diagnosis of type 1 autoimmune pancreatitis. Oral prednisolone treatment was initiated at 30 mg/day, and the dosage was gradually decreased. However, in accordance with the patient's wishes, maintenance treatment was discontinued once dosage reached 5 mg/day. Despite this, relapse of obstructive jaundice occurred 1 month post discontinuation, and was treated with methyl-prednisolone pulse therapy (500 mg/day) followed by oral prednisolone. However, computed tomography, magnetic resonance imaging, and endoscopic ultrasound did not reveal sufficient improvement after 6 months of treatment. Therefore, an immunosuppressant (azathioprine) was introduced. Subsequent imaging analyses and endoscopic ultrasound fine needle aspiration revealed clear improvements in pathology.

Mutation Profiling of Usual Ductal Hyperplasia of the Breast Reveals Activating Mutations Predominantly at Different Levels of the PI3K/AKT/mTOR Pathway

Usual ductal hyperplasia (UDH) of the breast is generally regarded as a nonneoplastic proliferation, albeit loss of heterozygosity has long been reported in a part of these lesions. To gain deeper insights into the molecular drivers of these lesions, an extended mutation profiling was performed. The coding regions of 409 cancer-related genes were investigated by next-generation sequencing in 16 cases of UDH, nine unassociated with neoplasia (classic) and seven arising within papillomas. Phosphatidylinositol 3-kinase/AKT/mammalian target of rapamycin (mTOR) activation was investigated by phosphorylated AKT, mTOR, and S6 immunohistochemistry. Of 16 lesions, 10 (63%) were mutated; 56% of classic lesions were unassociated with neoplasia, and 71% of lesions arose in papillomas. Fourteen missense mutations were detected: PIK3CA [6 (43%) of 14], AKT1 [2 (14%) of 14], as well as GNAS, MTOR, PIK3R1, LPHN3, LRP1B, and IGF2R [each 1 (7%) of 14]. Phosphorylated mTOR was seen in 83% and phosphorylated S6 in 86% of evaluable lesions (phospho-AKT staining was technically uninterpretable). In conclusion, UDH displays mutations of the phosphatidylinositol 3-kinase/AKT/mTOR axis at different levels, with PIK3R1, MTOR, and GNAS mutations not previously described. Specifically, oncogenic G-protein activation represents a yet unrecognized route to proliferation in UDH. On the basis of evidence of activating mutations, loss of heterozygosity, and a mass forming proliferation, we propose that UDH is most appropriately viewed as an early neoplastic intraductal proliferation.

Association Between Immunoglobulin G4-related Disease and Malignancy within 12 Years after Diagnosis: An Analysis after Longterm Followup

OBJECTIVE

Because it is uncertain whether immunoglobulin G4-related disease (IgG4-RD) is associated with malignancy, we evaluated the incidence of cancer development in a large cohort of patients with IgG4-RD.

METHODS

The study enrolled 158 patients diagnosed as having IgG4-RD between 1992 and 2012. We calculated the standardized incidence ratio (SIR) and cumulative rate of malignancies in this group and searched for risk factors associated with the occurrence of tumors.

RESULTS

A total of 34 malignancies were observed in the patients with IgG4-RD over a mean followup period of 5.95 ± 4.48 years. The overall SIR of malignancies was 2.01 (95% CI 1.34-2.69). The SIR of patients who exhibited a tumor within 1 year after IgG4-RD diagnosis was 3.53 (95% CI 1.23-5.83), while that of subjects forming a malignancy in subsequent years was 1.48 (95% CI 0.99-1.98). The cumulative rate of malignancy development was significantly higher in patients with IgG4-RD within 12 years after diagnosis than in the Japanese general population. Comparable results were obtained for an autoimmune pancreatitis subgroup. The serum concentrations of several disease activity markers at diagnosis were significantly higher in patients with malignancies than in those without.

CONCLUSION

We identified a close association between IgG4-RD and malignancy formation within 12 years after diagnosis, particularly during the first year. An active IgG4-RD state is presumed to be a strong risk factor for malignancy development.

Endoscopic ultrasound-guided fine-needle aspiration biopsy of autoimmune pancreatitis: diagnostic clues and pitfalls

INTRODUCTION

Autoimmune pancreatitis (AIP) is an inflammatory process that has characteristic clinical, radiographic, and pathologic features but may mimic pancreatic malignancy. In this study, we reviewed our experience in the endoscopic ultrasound-guided fine-needle aspiration evaluation of pancreatic lesions in patients with AIP.

MATERIALS AND METHODS

We searched the cytopathology archives and identified a total of 6 cases that had endoscopic ultrasound-guided fine-needle aspiration evaluation and subsequent tissue biopsy or resection with a diagnosis of AIP. The clinical, cytologic, and histopathologic features were reviewed.

RESULTS

The original cytologic diagnoses included negative, atypical, and suspicious for malignancy in 2 cases each. On retrospective review, these cases were characterized cytologically by the presence of mixed epithelial cells, mixed lymphocytes, and plasma cells, as well as cellular stromal fragments. Cytologic atypia of epithelial cells was observed in 4 of 6 cases, including mild (3 cases) and moderate (1 case) atypia. KRAS mutation analysis was performed in 4 cases with an indeterminate cytology diagnosis, which was negative in all cases.

CONCLUSIONS

Our results demonstrate that the presence of trilineage epithelial, lymphoplasmacytic, and stromal elements may be suggestive but not definitive for a diagnosis of AIP. The role of KRAS mutation analysis in AIP remains inconclusive and may warrant further evaluation.

Amendment of the Japanese Consensus Guidelines for Autoimmune Pancreatitis, 2013 III. Treatment and prognosis of autoimmune pancreatitis

The standard treatment for autoimmune pancreatitis (AIP) is steroid therapy, although some patients improve spontaneously. Indications for steroid therapy in AIP patients are symptoms such as obstructive jaundice, abdominal pain, back pain, and the presence of symptomatic extrapancreatic lesions. Prior to steroid therapy, obstructive jaundice should be managed by biliary drainage, and blood glucose levels should be controlled in patients with diabetes mellitus. The recommended initial oral prednisolone dose for induction of remission is 0.6 mg/kg/day, which is administered for 2-4 weeks. The dose is then tapered by 5 mg every 1-2 weeks, based on changes in clinical manifestations, biochemical blood tests (such as liver enzymes and IgG or IgG4 levels), and repeated imaging findings (US, CT, MRCP, ERCP, etc.). The dose is tapered to a maintenance dose (2.5-5 mg/day) over a period of 2-3 months. Cessation of steroid therapy should be based on the disease activity in each case. Termination of maintenance therapy should be planned within 3 years in cases with radiological and serological improvement. Re-administration or dose-up of steroid is effective for treating AIP relapse. Application of immunomodulatory drugs is considered for AIP patients who prove resistant to steroid therapy. The prognosis of AIP appears to be good over the short-term with steroid therapy. The long-term outcome is less clear, as there are many unknown factors, such as relapse, pancreatic exocrine or endocrine dysfunction, and associated malignancy.

Relationship between autoimmune pancreatitis and pancreatic cancer: a single-center experience

OBJECTIVES

Ordinary chronic pancreatitis (CP), such as alcoholic CP, is well established to have the increased risk for pancreatic cancer (PaC), nevertheless an association between autoimmune pancreatitis (AIP) and PaC is still unknown. The aims of this study are to examine the frequency of patients who developed PaC during follow-up after being diagnosed with type 1 AIP and to compare the incidence rate of PaC between patients with type 1 AIP and CP.

METHODS

Sixty-three patients with type 1 AIP and 41 patients with CP were enrolled. We examined development of PaC during follow-up from their clinical records.

RESULTS

The mean follow-up period was 62.4 months in AIP group and 49.2 months in CP group. The occurrence of PaC was observed in 3 patients with AIP during the mean follow-up period of 94.7 months (range, 31-186), whereas a single CP patient developed PaC 38 months after CP diagnosis. The incident rate of PaC during follow-up was comparable between the 2 groups [4.8% (3/63) in type 1 AIP group vs. 2.4% (1/41) in CP group]. In all of 3 AIP patients who developed accompanying PaC, the clinical remission of AIP was achieved with maintenance steroid therapy, when tumors were discovered. In the histological examination of one surgical patient with PaC, lymphoplasmacytic infiltration in storiform fibrosis with abundant IgG4-positive cell infiltration was observed around the PaC area.

CONCLUSIONS

Similar to patients with ordinary CP, surveillance for development of PaC is needed at regular interval during follow-up in AIP patients.

Association between autoimmune pancreatitis and malignancy

Chronic inflammatory diseases are often associated with malignancy, and this phenomenon occurs even in the field of gastroenterology. For example, chronic pancreatitis has been reported to be highly associated with the occurrence of pancreatic cancer. However, the association between autoimmune pancreatitis (AIP) and pancreatic cancer is still an unsolved problem. As AIP is associated with immunoglobulin G4-related disease, which causes a variety of inflammatory and fibrotic lesions, the association between AIP and total malignancies is also a matter of interest. Here, we discuss the association between AIP and malignancy. As for the association between AIP and pancreatic cancer, there is no conclusive evidence, although several reports have suggested that the relative risk of pancreatic cancer is high in AIP. Concerning the association between AIP and total malignancies, there are two reports from Japan. Neither report supported the idea that chronic inflammation in AIP caused the increased risk of total malignancies. However, one report proposed the possibility that AIP might develop as a paraneoplastic syndrome in some patients because many cancers occurred within 1 year of AIP diagnosis, and thereby concluded that patients with AIP were at high risk of having various cancers. The paraneoplastic syndrome hypothesis should be tested in future studies.

Current status of research on autoimmune pancreatitis

Autoimmune pancreatitis (AIP) is a form of chronic pancreatitis characterized clinically by frequent presentation with obstructive jaundice, histologically by lymphoplasmacytic infiltration with fibrosis, and therapeutically by a dramatic response to steroids. AIP have recently been classified into two subtypes, lymphoplasmacytic sclerosing pancreatitis (LPSP) and idiopathic duct centric pancreatitis (IDCP). The pathogenesis of AIP may involve genetic susceptibility, autoantibodies, molecular mimicry, imbalance of T-cell-mediated immune regulation, and gene mutation. In this article, we will systematically review typical and atypical clinical, imaging and histopathological features of AIP, with an emphasis placed on the advances in the diagnosis and treatment of this disease.

Cholangiocarcinoma developed in a patient with IgG4-related disease

A 77-year-old man with jaundice and a pancreatic head tumor was referred to our hospital in August 2006. The initial laboratory tests, computed tomography (CT) scan, magnetic resonance imaging (MRI), and endoscopic retrograde cholangiopancreatography suggested IgG4-related cholangitis and autoimmune pancreatitis. Oral prednisolone (PSL) was then administered. This treatment reduced the size of the pancreatic parenchyma, and the lower common bile duct (CBD) returned to its normal size. Thus, the oral PSL was gradually tapered to a maintenance dose. In February 2010, a CT scan and MRI showed segmental wall thickening and stenosis of the middle CBD, the progression of which led to extrahepatic obstructive jaundice. We suspected the emergence of a cholangiocarcinoma rather than the exacerbation of the IgG4-related sclerosing cholangitis because the stricture of the CBD was short and localized. Then, a percutaneous transhepatic biliary drainage was performed. The biopsy specimens obtained via the percutaneous transhepatic tract indicated an abnormal glandular formation, suggesting the presence of a moderate, well-differencated adenocarcinoma. The gross examination, microscopic examination and immunohistochemical analysis of the pancreaticoduodenectomy specimen suggested that a cholangiocarcinoma developed from the IgG4-related sclerosing cholangitis.

PRSS1_p.Leu81Met mutation results in autoimmune pancreatitis

AIM: To describe protease serine 1 (PRSS1) gene mutations in patients with autoimmune pancreatitis (AIP) and the clinical features of AIP.

METHODS: Fourteen patients with AIP, 56 with other chronic pancreatitis, 254 with pancreatic cancer and 120 normal controls were studied. The mutations and polymorphisms of four genes involved with pancreatitis or pancreatic cancer, PRSS1, SPINK1, CFTR and MEN1, were sequenced. The pathogenic mechanism of AIP was investigated by comparing the wild-type expression system with the p.81Leu→Met mutant expression system.

RESULTS: Two novel mutations (p.81Leu→Met and p.91Ala→Ala) were found in PRSS1 gene from four patients with AIP. PRSS1_p.81Leu→Met mutation led to a trypsin display reduction (76.2%) combined with phenyl agarose (Ca²⁺ induced failure). Moreover, the ratio of trypsin/amylase in patients with AIP was higher than in the patients with pancreatic cancer and other pancreatitis. A large number of lymphocytes and plasma cells were found in the bile ducts accompanied by hyperplasia of myofibroblasts.

CONCLUSION: Autoimmune pancreatitis may be related to PRSS1 gene mutations.

Does autoimmune pancreatitis increase the risk of pancreatic carcinoma?: a retrospective analysis of pancreatic resections

OBJECTIVES

To estimate the risk of malignancy in autoimmune pancreatitis (AIP).

METHODS

We examined resected pancreata to compare the prevalence of pancreatic intraepithelial neoplasia (PanIN) in 28 cases of AIP and 30 cases of chronic pancreatitis not otherwise specified (CP-NOS). We also reviewed a cohort of 84 AIP cases.

RESULTS

The mean age of the AIP cohort (57 years) was significantly higher than that of the cohort of CP-NOS (47 years) (P = 0.01). Twenty-three cases (82%) of AIP showed PanIN, and 7 cases (25%) showed grade 2 PanIN. Grade 3 PanIN was identified in one case of AIP. There was no statistically significant difference in the number of cases with high-grade PanIN lesions between the cases of type 1 as opposed to type 2 AIP. In comparison to CP-NOS, a comparable percentage of patients with AIP had PanIN (82% of AIP cases vs 63% of CP-NOS cases) (P = NS) and PanIN 2 (25% AIP vs 20% CP-NOS) (P = NS). Of the 84 AIP cases at our institution (mean follow-up, 49 months), 2 cases of pancreatic carcinoma were identified 6 and 10 years after the diagnoses of AIP.

CONCLUSIONS

These findings raise concern that AIP is associated with an elevated risk of malignancy and should prompt additional studies.

Immunological diseases of the pancreatico-hepatobiliary system: update on etiopathogenesis and cross-sectional imaging findings

Immunological diseases of the hepatobiliary system and the pancreas include a broad spectrum of disorders that manifest characteristic histopathology/serology and variable clinical features and imaging findings. Recent studies have thrown fresh light on the complex role of genetics and autoimmunity in the pathogenesis and natural history of these diverse disorders that include autoimmune hepatitis, primary biliary cirrhosis, primary sclerosing cholangitis, IgG4-related cholangitis, overlap/outlier syndromes, and autoimmune pancreatitis.

Importance of early diagnosis of pancreaticobiliary maljunction without biliary dilatation

AIM: To clarify the strategy for early diagnosis of pancreaticobiliary maljunction (PBM) without biliary dilatation and to pathologically examine gallbladder before cancer develops.

METHODS: The anatomy of the union of the pancreatic and bile ducts was assessed by using endoscopic retrograde cholangiopancreatography (ERCP). Patients with a long common channel in which communication between the pancreatic and bile ducts was maintained even during sphincter contraction were diagnosed as having PBM. Of these, patients in which the maximal diameter of the bile duct was less than 10 mm were diagnosed with PBM without biliary dilatation. The process of diagnosing 54 patients with PBM without biliary dilatation was retrospectively investigated. Histopathological analysis of resected gallbladder specimens from 8 patients with PBM without biliary dilatation or cancer was conducted.

RESULTS: Thirty-six PBM patients without biliary dilatation were diagnosed with gallbladder cancer after showing clinical symptoms such as abdominal or back pain (n = 16) or jaundice (n = 12). Radical surgery for gallbladder cancer was only possible in 11 patients (31%) and only 4 patients (11%) survived for 5 years. Eight patients were suspected as having PBM without biliary dilatation from the finding of gallbladder wall thickening on ultrasound and the diagnosis was confirmed by ERCP and/or magnetic resonance cholangiopancreatography (MRCP). The median age of these 8 patients was younger by a decade than PBM patients with gallbladder cancer. All 8 patients underwent prophylactic cholecystectomy and bile duct cancer has not occurred. Wall thickness and mucosal height of the 8 resected gallbladders were significantly greater than controls, and hyperplastic changes, hypertrophic muscular layer, subserosal fibrosis, and adenomyomatosis were detected in 7 (88%), 5 (63%), 7 (88%) and 5 (63%) patients, respectively. Ki-67 labeling index was high and K-ras mutation was detected in 3 of 6 patients.

CONCLUSION: To detect PBM without biliary dilatation before onset of gallbladder cancer, we should perform MRCP for individuals showing increased gallbladder wall thickness on ultrasound.

Autoimmune pancreatitis: an update on classification, diagnosis, natural history and management

Autoimmune Pancreatitis (AIP) is a recently recognized chronic fibro-inflammatory disease of the pancreas. Although rare, its recognition continues to increase worldwide. Patients often present with painless obstructive jaundice mimicking pancreatic cancer. Two subtypes of AIP are known-type 1 is a multi-organ disease associated with IgG4; type 2 appears to be a pancreas-specific disorder. Dramatic response to steroid treatment is characteristic of both forms. A non-invasive diagnosis of type 1 AIP may be possible using diagnostic criteria (in ~70% cases) while diagnosis of type 2 requires histology. These subtypes differ in natural history- type 1 often relapses while initial reports suggest that type 2 does not. Long term complications include endocrine and exocrine insufficiency and in case of type 1, disease relapses and complications from extra-pancreatic involvement. Neither form affects long term survival. The treatment and follow-up guidelines continue to evolve with our increasing experience in AIP.

Clinical impact of K-ras mutation analysis in EUS-guided FNA specimens from pancreatic masses

BACKGROUND

EUS-guided FNA (EUS-FNA) is considered optimal for differentially diagnosing pancreatic masses. However, the sensitivity of EUS-FNA ranges from 65% to 95%, respectively, which requires improvement.

OBJECTIVE

To evaluate clinical impact of K-ras mutation analysis in EUS-FNA specimens from pancreatic masses.

DESIGN

Prospective registration, single-center study.

SETTING

Tertiary referral center.

PATIENTS

This study involved 394 consecutive patients with pancreatic masses (307 pancreatic ductal adenocarcinomas [PDACs], 47 pancreatic inflammatory lesions, and 40 other types of tumors) who underwent EUS-FNA and analysis of K-ras mutations.

INTERVENTION

EUS-FNA, Cycleave polymerase chain reaction.

MAIN OUTCOME MEASUREMENTS

Improvement of the diagnostic accuracy by K-ras mutation analysis; absence of K-ras mutations in non-PDAC masses.

RESULTS

K-ras mutations were detected in 266 of 307 PDAC aspirates (87%) and in 3 of 87 non-PDAC masses (3%). K-ras mutations were detected in 18 of 39 patients (46%) who remained cytohistopathologically undiagnosed. The sensitivity, specificity, positive and negative predictive values, and accuracy of cytohistopathological and K-ras mutation analyses alone were 87%, 100%, 100%, 54%, and 89%, respectively, and, when combined, were 93%, 100%, 100%, 68%, and 94%, respectively. Adding K-ras mutation analysis to standard cytohistopathological assessment increased the sensitivity and accuracy of EUS-FNA by 6% (P < .001) and 5% (P < .001), respectively.

LIMITATIONS

Single-center study.

CONCLUSIONS

K-ras mutation analysis may be helpful in patients with suspected PDAC yet inconclusive EUS-FNA findings. K-ras mutations were extremely rare in pancreatic inflammation and other pancreatic tumors.

Detection of KRAS gene mutations in endoscopic ultrasound-guided fine-needle aspiration biopsy for improving pancreatic cancer diagnosis

OBJECTIVES

Endoscopic ultrasound-guided fine-needle aspiration biopsy (EUS-FNAB) is a useful tool in the diagnosis of pancreatic masses. Genetic analysis of these samples could increase the sensitivity and specificity of diagnosis. This study aimed to evaluate the usefulness of a novel method for the detection of mutations in the KRAS (Kirsten rat sarcoma-2 virus) gene for the diagnosis of pancreatic cancer.

METHODS

EUS-FNABs were performed on 82 patients with pancreatic masses, including 54 cases of pancreatic ductal adenocarcinoma and 28 of non-malignant pancreatic masses. The biopsies were histopathologically and cytopathologically evaluated, and the detection of KRAS gene mutations (codons 12 and 13) was performed through peptide nucleic acid-directed polymerase chain reaction clamping and DNA sequencing.

RESULTS

In the pancreatic cancer cases, 88.9% (48/54; 95% confidence interval (CI): 80.5-97.2%) had KRAS mutations, while 61.1% (33/54; 95% CI: 48.1-74.1%) were unequivocally diagnosed by histo/cytopathology. In the indeterminate patients (n=49; diagnosed by EUS-FNA as either insufficient material to make a diagnosis, no malignancy, or suspicion of malignancy), there were 10 cases of pancreatic cancer with low serum carbohydrate antigen 19-9 (CA19-9) (<37 U/l) and 6 of these were KRAS mutations. The sensitivity of detection by KRAS mutations (76.2%) and the combination of KRAS mutations and serum CA19-9 (81%) were significantly higher than for serum CA19-9 alone (52.4%). A logistic regression model showed that the KRAS mutation was significant (odds ratio=5.830; CI: 1.531-22.199, P=0.01), but not serum CA19-9. In the non-malignant pancreatic masses (n=28), KRAS mutations were detected in nine precancerous lesions.

CONCLUSIONS

Our method for the detection of KRAS gene mutations may be useful to supplement histo/cytopathologic evaluations for pancreatic cancer, and is superior to serum CA19-9 in EUS-FNAB histo/cytopathology-indeterminate patients. Results warrant further verification in other patient populations.

Pancreatic ductal adenocarcinoma associated with autoimmune pancreatitis

Autoimmune pancreatitis (AIP), in contrast to other benign chronic pancreatic diseases, can be cured with immunosuppressant drugs, thus the differentiation of AIP from pancreatic cancer is of particular interest in clinical practice. There is the possibility that some patients with AIP may develop pancreatic cancer, and this possibility contributes to increasing our difficulties in differentiating AIP from pancreatic cancer. We herein report the case of a 70-year-old man in whom pancreatic adenocarcinoma and AIP were detected simultaneously. We must carefully monitor AIP patients for the simultaneous presence of pancreatic cancer, even when a diagnosis of AIP is confirmed.

Autoimmune pancreatitis and biliary intraepithelial neoplasia of the common bile duct: a case with diagnostically challenging but pathogenetically significant association

Autoimmune pancreatitis (AIP) (also called IgG4-related sclerosing pancreatitis (IgG4-SP)) and IgG4-related sclerosing cholangitis (IgG4-SC) are frequently associated with each other. It is generally believed that association of these diseases with pancreatobiliary malignancy is, however, rare. Here, we report on the case of a patient with AIP whose biliary cytology revealed severely atypical cells. Surgically resected specimens from this patient showed typical AIP with IgG4-SC, as well as a mildly elevated lesion in the common bile duct with varying degrees of cellular atypia. In addition, the atypical cells tested positive for the mucin-core protein, MUC5AC and p53 overexpression. These findings led us to diagnose the common bile duct lesion as biliary intraepithelial neoplasia (BilIN, mainly BilIN-1/2). Recently, associations between K-ras mutations and pancreatobiliary carcinoma have been reported in patients with AIP. This case, therefore, provides important new insight into the potential association of AIP and/or IgG4-SC with malignancy (or precursor lesions) of the pancreatobiliary system.

An unusual case of autoimmune pancreatitis presenting as pancreatic mass and obstructive jaundice: a case report and review of the literature

Background

Autoimmune pancreatitis is a rare chronic inflammatory pancreatic disease that is increasingly being diagnosed worldwide. As a result of overlap in clinical and radiological features, it is often misdiagnosed as pancreatic cancer. We report the case of a patient with autoimmune pancreatitis that was initially misdiagnosed as pancreatic cancer.

Case presentation

A 31-year-old Caucasian man presented to our hospital with epigastric pain, jaundice and weight loss. His CA 19-9 level was elevated, and computed tomography and endoscopic ultrasound revealed a pancreatic head mass abutting the portal vein. Endoscopic retrograde cholangiopancreaticography showed narrowing of the biliary duct and poor visualization of the pancreatic duct. Fine-needle aspiration biopsy revealed atypical ductal epithelial cells, which raised clinical suspicion of adenocarcinoma. Because of the patient's unusual age for the onset of pancreatic cancer and the acuity of his symptoms, he was referred to a tertiary care center for further evaluation. His immunoglobulin G4 antibody level was 365 mg/dL, and repeat computed tomography showed features typical of autoimmune pancreatitis. The patient's symptoms resolved with corticosteroid therapy.

Conclusion

Autoimmune pancreatitis is a rare disease with an excellent response to corticosteroid therapy. Its unique histological appearance and response to corticosteroid therapy can reduce unnecessary surgical procedures. A thorough evaluation by a multidisciplinary team is important in rendering the diagnosis of autoimmune pancreatitis.