Autoimmune pancreatitis mimicking pancreatic cancer

Avoiding Unnecessary Surgery in Autoimmune Pancreatitis: Lessons From a Four-Patient Case Series and Literature Review

Autoimmune pancreatitis (AIP) is an inflammatory disease that may be mistaken for pancreatic cancer, especially when there is a focal lesion in the pancreatic head. It often involves biliary strictures and occasional tumor marker elevations, causing confusion with malignancy. An incomplete assessment might lead to unwarranted surgery for what is actually an inflammatory process. By combining imaging, histopathology, IgG4 measurement, and the clinical response to steroids, physicians can reach the correct diagnosis more reliably. We describe four adults, ages 64 to 84, who had obstructive jaundice, biliary dilation, and imaging findings suggesting a possible pancreatic head tumor. Tumor marker levels varied; some were elevated, while others were unremarkable. In two instances, imaging raised concerns about vascular involvement. Endoscopic ultrasound-guided biopsies showed lymphoplasmacytic inflammation without malignant cells, and all patients had elevated IgG4 levels that decreased with steroid therapy. Each individual underwent endoscopic biliary stenting and began a course of prednisone, leading to a return of normal liver function and improvement in imaging findings. Two required short-term additional stent management for persistent strictures, and three underwent gallbladder removal due to associated disease. All four avoided major pancreatic surgery and had a favorable clinical course. These cases show the importance of a methodical workup that includes IgG4 assessment and biopsy confirmation. Steroid therapy can resolve clinical and radiologic abnormalities once AIP is recognized. This approach spares many patients from extensive operations when their presumed neoplasm is, in reality, an autoimmune condition.

IgG4-related disorders of the gastrointestinal tract: Experience from a tertiary care centre with systematic review of Indian literature

INTRODUCTION

IgG4-related disease (IgG4-RD) is a rare disease entity in India. We aimed at studying the clinical profile of IgG4-RD of gastrointestinal tract (GIT) from our centre, while systematically reviewing data from India.

METHODS

Retrospective review of IgG4-RD of GIT was done using electronic medical records between January 2013 and July 2022. Literature search was done for studies of IgG4-RD of the GIT reported from India from 2000 till January 2023. Case series, case reports of IgG4-RD of GIT and case reports describing GIT with multi-organ involvement were included in the review. Primary outcome measure was response to treatment. Secondary outcome measure was relapse after remission.

RESULTS

Thirty-one patients were included with 71% (22/31) having autoimmune pancreatitis. The diagnosis was achieved on surgical specimen in 35% (11/31) patients. Steroid was given to 64% (20/31) patients with remission achieved in 70% (14/20) patients. Four patients exhibitted response to prolonged course of steroids with maintenance azathioprine. Relapse was seen in four (20%) patients who achieved remission. Of 731 articles screened, 48 studies (four case series and 44 case reports) were included in the literature review. Of 95 patients described, steroids were given to 65.2% (62/95), while surgery was done in 33.6% (32/95). Remission was seen in 96.6% (85/88) with relapse occurring in 11.4% (10/88) patients on follow-up.

CONCLUSION

One-third patients of IgG4-RD of GIT are diagnosed after surgery. Response to steroids is good with relapse occurring in up to 12% patients.

A Diagnostic Challenge: Pancreatic Cancer or Autoimmune Pancreatitis?

ABSTRACT: We report a rare case of seronegative autoimmune pancreatitis (AIP) that presented as a pancreatic focal lesion and was considered to be pancreatic cancer based on the clinical presentation and imaging findings. The endoscopic ultrasound-guided biopsies of the pancreatic mass revealed no malignant cells and the pancreatic swelling had become diffuse on repeat imaging. AIP was suspected and a trial of steroids was considered as a diagnostic and therapeutic method. The patient responded dramatically to corticosteroid treatment with resolution of symptoms and normal imagining and laboratory parameters. This case highlights the challenge in the diagnostic approach of a pancreatic mass.

A Solid Pseudopapillary Neoplasm of the Pancreas Associated With IgG4-Related Pancreatitis: A Case Report

A solid and cystic pancreatic lesion was incidentally found in a 62-year-old woman on abdominal computed tomography. The lesion was diagnosed as a solid pseudopapillary neoplasm by using endoscopic ultrasound-guided fine needle aspiration, and the tumor was resected. Histologically, the tumor cells had relatively small, round nuclei and papillary-like architecture in a hemorrhagic background. On immunohistochemical examination, the tumor cells were diffusely positive for nuclear β-catenin and cytoplasmic CD10. In addition, typical histological findings of IgG4-related pancreatitis (obstructive phlebitis, storiform-type fibrosis, and abundant IgG4-positive plasma cell infiltration) were found in the surrounding stroma of the solid pseudopapillary neoplasm. Postoperative workup failed to detect any other sclerotic lesions or serum IgG4 elevation, suggesting that the patient had no evidence of IgG4-related disease. To avoid misdiagnosis of a combined pancreatic neoplasm and fibro-inflammatory lesion, pathologists should consider such situations and make a definitive diagnosis after careful observation of all pancreatic lesions.

Changing trends in tissue acquisition in malignant pancreatic neoplasms

BACKGROUND AND AIM

To compare the frequency of use, hospital costs, and resource availability between endoscopic ultrasound-guided fine needle aspiration (EUS-FNA), percutaneous, and surgical techniques for tissue acquisition in malignant pancreatic neoplasms.

METHODS

This is a retrospective claims analysis of Medicare patients undergoing biopsy of malignant pancreatic neoplasms over 5 years (2006-2010). The primary outcome measure was to compare the utilization of EUS, percutaneous techniques, and surgery for performing pancreatic biopsies. The secondary outcome measures were to compare treatment costs and variations in availability of resources between the three techniques over a 1-year period (2010).

RESULTS

Over 5 years, the use of EUS-FNA increased by 69.3% (7100 to 12 020) and the use of percutaneous biopsy by 1.8% (4480 to 4560) compared to decrease in surgical biopsy (720 to 420) by 41.7% (P < 0.0001). When compared to percutaneous and surgical biopsies ($9639 and $21 947, respectively) the median hospital cost/claim for EUS-FNA ($1794) was significantly lower (P < 0.0001). More EUS-FNA procedures were performed in urban and teaching hospitals compared to rural and non-teaching hospitals (P < 0.001).

CONCLUSIONS

Although EUS-FNA is increasingly performed and is less costly, and the rate of surgical biopsies has declined precipitously, the utilization of percutaneous techniques remains prevalent. Training and education are required to disseminate the use of EUS-FNA outside major teaching institutions or foster referral of patients to EUS centers because of implications for patient care and resource use.

Follicular pancreatitis, report of a case clinically mimicking pancreatic cancer and literature review

We herein present a 71-year-old man who underwent pancreatoduodenectomy with the diagnosis of follicular pancreatitis. We could not completely deny malignancy by a preoperative imaging study. Endoscopic ultrasonography-guided fine needle aspiration biopsy demonstrated clusters of benign acinar cells and no proliferation of atypical lymphoid cells or rich plasma cells. Histologically, the prominent lymphoid follicle formation was seen in an ill-defined mass, 15 mm in size, in the pancreatic parenchyma. Duct-centered fibrotic rims were seen in the pancreatic ducts accompanied by mild fibrotic change between the follicles and obliterative phlebitis. No neoplastic epithelial cells were observed in the resected specimen, and infiltrating lymphocytes did not show any morphological atypia and monoclonal proliferation by immunohistochemical staining with B and T cell markers. In addition, we could exclude IgG4-related disease, because plasmacytic cells were rarely positive for IgG4. Although follicular pancreatitis is rare, this mass-forming inflammatory disease (pancreatitis) should be included in the preoperative differential diagnosis of pancreatic cancer.

Clinical analysis of 36 cases of autoimmune pancreatitis in China

BACKGROUND

To improve the early identification of autoimmune pancreatitis in China by a retrospective analysis of clinical data from AIP patients.

METHODOLOGY/PRINCIPAL FINDINGS

The analysis included 36 patients admitted by the surgery department of our hospital from January 2003 to October 2011 whose postoperative pathological confirmations were consistent with the histological criteria of Honolulu Consensus Document. The clinical phenotypes associated with the histopathologic patterns of LPSP and IDCP were referred to as type 1 and type 2 of AIP, respectively. A retrospective analysis of clinical features, serological data, pathological findings and imageological records was performed in line with the subtypes of AIP. Type 1 showing a sex predilection (males) was commonly more dominant than type 2 in all AIP. Type 2 without a gender predilection was, on average, a decade younger than type 1. Type 1 was inferior to type 2 in ALT, ALP and γ-GT with statistical significance (P = 0.044, 0.025 and 0.013). Type 1 was inferior to type 2 in AST with difference close to statistical significance (P = 0.072). Histopathology revealed frequent lymphoplasmacytic infiltration with less frequent infiltration of neutrophils, eosinophils and fibroblasts. Diffuse and intensive interstitial fibrosis could be seen. The changes of pancreatic head were more frequently seen in type 2 than in type 1 (P = 0.05). Plasma cells staining of IgG4 at a density of over 30 or more cells per high-power field appeared to be a specific finding in China with type 1. Imageology found a diffusely or focally enlarged pancreas, most frequently a mass or enlargement in the pancreatic head, characteristic capsule-like rim, calcification or pancreatic calculus and cystic degeneration.

CONCLUSIONS/SIGNIFICANCE

AIP is a unique type of chronic pancreatitis and has distinctive serological, pathological and imageological characteristics, which should be used for differentiation from pancreatic cancer.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Relationship between pancreatic and/or extrapancreatic lesions and serum IgG and IgG4 levels in IgG4-related diseases

OBJECTIVE

We aimed to investigate the relationship between the number of involved organs or regions and serum immunoglobulin G (IgG) and immunoglobulin G4 (IgG4) levels.

METHODS

The number of pancreatic and/or extrapancreatic lesions and serum IgG and IgG4 levels were examined by groups in 46 patients with IgG4-related diseases at diagnosis prior to the initiation of steroid treatment: group A (one region involved, n=7), group B (two regions involved, n=11), group C (three regions involved, n=12), group D (four regions involved, n=9) and group E (five to seven regions involved, n=7).

RESULTS

Both serum IgG and IgG4 levels increased with the number of inflamed regions. Mean serum IgG levels were 15.11, 18.65, 20.92, 23.29 and 30.98 g/L while the mean IgG4 levels were 3.99, 4.70, 4.70, 9.86 and 16.49 g/L in group A, B, C, D and E, respectively. Regression analysis also suggested that IgG4 was positively correlated with the number of regions involved. Additionally, serum IgG4 was higher in patients with multiple lesions when accompanied by sclerosing sialadenitis.

CONCLUSION

Patients having IgG4-related disease with high serum IgG and IgG4 levels should be systematically examined for involved lesions.

Differentiation of autoimmune pancreatitis with pancreatic carcinoma remains a challenge to physicians

OBJECTIVE

The aim of this study was to summarize the clinical features of autoimmune pancreatitis (AIP) and review the advances in the differential diagnosis with pancreatic carcinoma, thus help to make a correct diagnosis and avoid unnecessary surgery in clinical practice.

METHODS

Five patients diagnosed as AIP in accordance with the HISORt criteria in Zhongshan Hospital, Fudan University from 2008 to 2010 were enrolled in the study. Clinical features were analyzed and related literature was reviewed.

RESULTS

Progressive jaundice and abdominal pain were the most frequent symptoms, as well as weight loss, together with serological changes such as elevation of alkaline phosphatase, γ-glutamyl-transpeptidase and serum bilirubin. Two of them showed high serum immunoglobulin G4 (IgG4) levels. Both focal and diffuse changes were found on computed tomography and magnetic resonance imaging. Two of our patients underwent operation because of a high suspicion of malignant tumor, and steroid therapy was administered to the other three patients diagnosed as AIP. No relapse was observed during the follow-up duration of all the patients.

CONCLUSIONS

Although some recent advances have been made to help the diagnosis of AIP, the differentiation between AIP and pancreatic carcinoma is still a challenge. Clinicians must remember to exclude AIP before making a diagnosis of pancreatic carcinoma.

Histopathologically proven autoimmune pancreatitis mimicking neuroendocrine tumor or pancreatic cancer

Autoimmune pancreatitis (AIP) can be difficult to distinguish from pancreatic cancer. We report a case of histopathologically proven AIP mimicking neuroendocrine tumor (NET) or pancreatic cancer in a 53-year-old man. He was referred to our hospital for further evaluation of a pancreatic mass detected on ultrasonography at a medical check-up. Abdominal ultrasonography showed a 15-mm hypoechoic mass located in the pancreatic body. Computed tomography revealed a tumor without any contrast enhancement, and magnetic resonance imaging demonstrated the mass to be hyperintense on diffusion-weighted image. Endoscopic retrograde cholangiopancreatography revealed slight dilatation of a branch of the pancreatic duct without stricture of the main pancreatic duct. The common bile duct seemed intact. Under suspicion of a non-functioning NET or malignant neoplasm, laparotomy was performed. At laparotomy, an elastic firm and well-circumscribed mass was found suggestive of a non-functioning NET, thus enucleation was performed. Histopathologically, the lesion corresponded to AIP.

Autoimmune pancreatitis characterized by predominant CD8+ T lymphocyte infiltration

Autoimmune pancreatitis (AIP) is a rare form of pancreatitis characterized by prominent lymphocyte infiltration and pancreatic fibrosis resulting in organ dysfunction. The pathogenesis and pathology of AIP remain unknown. A 64-year-old Chinese man presented with symptoms and signs of bile duct obstruction diffuse enlargement of the head of pancreas, elevated IgG levels, and negative autoimmune antibody responses. A pylorus-preserving pancreatoduodenectomy was performed and a pancreatic tumor was suspected. However, periductal lymphoplasmacytic infiltration and fibrosis were found in the head of pancreas and nearby organs instead of tumor cells. Four months after surgery, the patient was readmitted because of reoccurrence of severe jaundice and sustained abdominal distension. Prednisone 30 mg/d was administered orally as an AIP was suspected. One and a half months later, the symptoms of the patient disappeared, and globulin, aminotransferase and bilirubin levels decreased significantly. Over a 9-mo follow-up period, the dose of prednisone was gradually decreased to 10 mg/d and the patient remained in good condition. We further demonstrated dominant CD3+/CD8+ populations, CD20+ cells and a few CD4+ cells in the pancreatic parenchyma, duodenum and gallbladder wall by immunohistochemical assay. This AIP case presented with significant CD8+ T lymphocyte infiltration in the pancreas and extra-pancreatic lesions, indicating that this cell population may be more important in mediating AIP pathogenesis than previously known and that AIP might be a poorly defined autoimmune disease with heterogeneous pathogenesis.