Eosinophilic pancreatitis: Three case reports and literature review

Eosinophilic pancreatitis with serum IgG4-positivity, potentially associated with autoimmune pancreatitis

A 70-year-old man presented with unprovoked weight loss and intermittent left upper quadrant tenderness for one-and-a-half month. Computed tomography revealed irregular cystic lesions in the pancreatic tail. Endoscopic ultrasonography (EUS) revealed pancreatic tail enlargement and giant, thick-walled cysts surrounding the pancreatic tail with no connection with the pancreatic duct. Endoscopic ultrasonography-guided fine-needle aspiration was performed on the enlarged pancreatic parenchyma and thickened cyst wall. Both biopsies showed hyper eosinophilia and few plasma cells. Endoscopic retrograde pancreatography revealed an irregular narrowing of the main pancreatic duct. Pancreatic juice cytology revealed substantial eosinophilia. Blood sampling showed an elevated eosinophil count and immunoglobulin G4 (IgG4) and immunoglobulin E (IgE) levels at the initial examination. We considered the patient to have eosinophilic pancreatitis (EP) with autoimmune pancreatitis, or alternately, EP with IgG4-related retroperitoneal fibrosis (RPF). Upon prednisolone administration, the abdominal pain improved, the peripheral blood eosinophil count decreased to zero, IgG4 and IgE levels decreased, pancreatic enlargement improved, and the cystic lesions disappeared. The condition did not recur within the following 3 years. Both EP and EP with IgG4-related RPF are rare etiologies of pancreatitis, and this case is very instructive.

Eosinophilic pancreatitis presenting as rupture of a pancreatic cystic lesion into the chest cavity

A 71-year-old man was receiving follow-up examination because of a retention cyst in the pancreatic body that extended to the dorsal extrahepatic area, but presented to the Emergency Department at our hospital with dyspnea and cough. Chest X-ray showed a large amount of left-sided pleural effusion and abdominal computed tomography (CT) showed reduction in size of the cystic lesion. Biochemical testing of the pleural effusion revealed high levels of pancreatic enzymes. We, therefore, diagnosed rupture of the pancreatic cystic lesion into the chest cavity. Endoscopic retrograde cholangiopancreatography (ERCP) demonstrated stenosis of the pancreatic duct and leakage of contrast medium at the cystic lesion. CT after ERCP revealed leakage of contrast medium from the cystic lesion through the dorsal extrahepatic area into the chest cavity. Endoscopic naso-pancreatic drainage was performed, but the cystic lesion and pleural effusion remained unimproved. Distal pancreatectomy was, therefore, performed. Microscopic examination revealed eosinophilic infiltration of the pancreatic parenchyma, leading to a diagnosis of eosinophilic pancreatitis (EP). Pancreatic retention cyst secondary to chronic pancreatitis associated with eosinophilic infiltration was considered to have ruptured into the chest cavity. EP is a rare etiology of pancreatitis and few cases have been reported. This case was thus considered valuable.

Chronic Pancreatitis and the Development of Pancreatic Cancer

Pancreatitis is a fibro-inflammatory disorder of the pancreas that can occur acutely or chronically as a result of the activation of digestive enzymes that damage pancreatic cells, which promotes inflammation. Chronic pancreatitis with persistent fibro-inflammation of the pancreas progresses to pancreatic cancer, which is the fourth leading cause of cancer deaths across the globe. Pancreatic cancer involves cross-talk of inflammatory, proliferative, migratory, and fibrotic mechanisms. In this review, we discuss the role of cytokines in the inflammatory cell storm in pancreatitis and pancreatic cancer and their role in the activation of SDF1α/CXCR4, SOCS3, inflammasome, and NF-κB signaling. The aberrant immune reactions contribute to pathological damage of acinar and ductal cells, and the activation of pancreatic stellate cells to a myofibroblast-like phenotype. We summarize several aspects involved in the promotion of pancreatic cancer by inflammation and include a number of regulatory molecules that inhibit that process.

Macrophages-induced IL-18-mediated eosinophilia promotes characteristics of pancreatic malignancy

The current study presents first CP murine model that show IL-18–induced eosinophil inflammation-mediated induction of oncogenic proteins and several pathological malignant characteristics.

Reports indicate that accumulated macrophages in the pancreas are responsible for promoting the pathogenesis of chronic pancreatitis (CP). Recently, macrophage-secreted cytokines have been implicated in promoting pancreatic acinar-to-ductal metaplasia (ADM). This study aims to establish the role of accumulated macrophage-activated NLRP3-IL-18-eosinophil mechanistic pathway in promoting several characteristics of pancreatic malignancy in CP. We report that in a murine model of pancreatic cancer (PC), accumulated macrophages are the source of NLRP3-regulated IL-18, which promotes eosinophilic inflammation-mediated accumulation to periductal mucin and collagen, including the formation of ADM, pancreatic intraepithelial neoplasia (PanINs), and intraductal papillary mucinous neoplasm. Most importantly, we show improved malignant characteristics with reduced levels of oncogenes in an anti–IL-18 neutralized and IL-18 gene deficient murine model of CP. Last, human biopsies validated that NLRP3-IL-18–induced eosinophils accumulate near the ducts, showing PanINs formation in PC. Taken together, we present the evidence on the role of IL-18–induced eosinophilia in the development of PC phenotype like ADM, PanINs, and ductal cell differentiation in inflammation-induced CP.

Eosinophils in the pathogenesis of pancreatic disorders

Eosinophils comprise approximately 1-4% of total blood leukocytes that reside in the intestine, bone marrow, mammary gland, and adipose tissues to maintain innate immunity in healthy individuals. Eosinophils have four toxic granules known as major basic protein (MBP), eosinophil cationic protein (ECP), eosinophil peroxidase (EPO), and eosinophil-derived neurotoxin (EDN), and upon degranulation, these granules promote pathogenesis of inflammatory diseases like allergy, asthma, dermatitis, and gastrointestinal disorders. Additionally, the role of eosinophils is underscored in exocrine disorders including pancreatitis. Chronic pancreatitis (CP) is an inflammatory disorder that occurs due to the alcohol consumption, blockage of the pancreatic duct, and trypsinogen mutation. Eosinophil levels are detected in higher numbers in both CP and pancreatic cancer patients compared with healthy individuals. The mechanistic understanding of chronic inflammation-induced pancreatic malignancy has not yet been reached and requires further exploration. This review provides a comprehensive summary of the epidemiology, pathophysiology, evaluation, and management of eosinophil-associated pancreatic disorders and further summarizes current evidence regarding risk factors, pathophysiology, clinical features, diagnostic evaluation, treatment, and prognosis of eosinophilic pancreatitis (EP) and pancreatic cancer.

Eosinophilic pancreatitis presenting as possible malignancy

Eosinophilic pancreatitis is a rare form of chronic pancreatitis that is often mistaken for malignancy due to nonspecific presenting symptoms and noncontributory auxiliary exams. This clinical case report highlights a unique presentation of chronic pancreatitis. A middle-aged man developed abdominal pain, and repeat imaging showed an interval increase in size of a known pancreatic lesion. A core biopsy showed benign pancreatic tissue with eosinophilic-rich inflammation; IgE levels were also elevated. The patient was started on a prednisone taper, and repeat computed tomography 3 months later showed a decreased size of the pancreatic lesion. Correct and timely diagnosis of eosinophilic pancreatitis may avoid invasive unnecessary surgical procedures and allow for earlier initiation of appropriate therapy.

Eosinophilic pancreatitis: a review of the pathophysiology, diagnosis, and treatment

Eosinophilic pancreatitis (EP) is an extremely rare disease caused by purely eosinophilic infiltration of the pancreas. EP is prone to being misdiagnosed as pancreatic cancer, causing unnecessary economic and physical harm to the patient. We report three cases of EP that were cured by steroids without relapse from 2017 to now. The clinical data of the three patients, including clinical manifestations, serological manifestations, imaging (ultrasound, computed tomography, and MRI), pathological diagnosis and treatment, and telephone follow-up of all patients, were retrospectively analysed. In addition, a literature search was conducted on the Web of Science and PubMed databases using key terms related to EP, considering case reports with no restrictions on the date of publication or language. In conclusion, we analysed 19 cases and determined the diagnostic criteria for EP. The diagnostic algorithm for EP can be used to diagnose EP easily. We hope that our standards and algorithm can reduce the rate of misdiagnosis and contribute to clinical diagnosis and treatment. In addition, we expect to evaluate more EP cases to test our diagnostic criteria and design a systematic diagnostic flow chart.

Experimental Modeling of Eosinophil-Associated Diseases

Eosinophils are an important subtype of leukocytes derived from bone marrow multipotent hematopoietic stem cells and represent about 1% of leukocytes in circulating blood. In homeostatic conditions, eosinophils reside in the intestine to maintain the balance of immune responses by communicating with gut microbes without causing inflammation. However, under the stressed or diseased condition, eosinophils degranulate, releasing their granule-derived cytotoxic proteins that are involved in inflammatory responses. Various eosinophil-associated inflammatory diseases are eosinophilic esophagitis (EoE), eosinophilic gastroenteritis (EG), and eosinophilic colitis (EC), together called EGID, asthma, hypereosinophilic syndrome, and eosinophilic pneumonia (EP). Eosinophil degranulation results in the release of their four toxic proteins [major basic protein (MBP), eosinophil cationic protein (ECP), eosinophil peroxidase (EPO), and eosinophil-derived neurotoxin (EDN)] which promote disease pathogenesis. Pancreatitis is the inflammatory disease of the pancreas that arises due to blockage of the pancreatic duct, trypsinogen mutation, alcohol consumption, and repeated occurrence of pancreatitis leading to chronic pancreatitis (CP); subsequently some CP patients may also develop pancreatic cancer. The presence of eosinophils is now shown in various case reports with acute, recurrent acute, and chronic pancreatitis and pancreatic cancer indicating the role of eosinophils in the pathogenesis of various pancreatic inflammatory disorders. However, the details of eosinophil accumulation during pancreatic diseases are not well explored and need further attention. Overall, the chapter provides the current understanding of reported eosinophils associated with inflammatory diseases like EGID diseases, asthma, and pancreatic disorders, i.e., acute, chronic pancreatitis, and pancreatic cancer. This knowledge will be helpful for future studies to develop novel treatment options for the eosinophils associated diseases. Therefore, more efforts are needed to perform preclinical and clinical studies in this field for the successful development of eosinophil-targeting treatments for a variety of eosinophil-associated diseases.

Characteristic pancreatic and splenic immune cell infiltration patterns in mouse acute pancreatitis

BACKGROUND

A systemic evaluation of immune cell infiltration patterns in experimental acute pancreatitis (AP) is lacking. Using multi-dimensional flow cytometry, this study profiled infiltrating immune cell types in multiple AP mouse models.

METHODS

Three AP models were generated in C57BL/6 mice via cerulein (CAE) injection, alcohol and palmitoleic acid (EtOH + POA) injection, and alcohol diet feeding and cerulein (EtOH + CAE) injection. Primary pancreatic cells and splenocytes were prepared, and multi-dimensional flow cytometry was performed and analyzed by manual gating and computerized PhenoGraph, followed by visualization with t-distributed stochastic neighbor embedding (t-SNE).

RESULTS

CAE treatment induced a time-dependent increase of major innate immune cells and a decrease of follicular B cells, and TCD4+ cells and the subtypes in the pancreas, whereas elicited a reversed pattern in the spleen. EtOH + POA treatment resulted in weaker effects than CAE treatment. EtOH feeding enhanced CAE-induced amylase secretion, but unexpectedly attenuated CAE-induced immune cell regulation. In comparison with manual gating analysis, computerized analysis demonstrated a remarkable time efficiency and reproducibility on the innate immune cells and B cells.

CONCLUSIONS

The reverse pattern of increased innate and decreased adaptive immune cells was consistent in the pancreas in CAE and EtOH + POA treatments. Alcohol feeding opposed the CAE effect on immune cell regulation. Together, the immune profiling approach utilized in this study provides a better understanding of overall immune responses in AP, which may facilitate the identification of intervention windows and new therapeutic strategies. Computerized analysis is superior to manual gating by dramatically reducing analysis time.

Eosinophilic pancreatitis versus pancreatitis associated with eosinophilic gastroenteritis - a systematic review regarding clinical features and diagnosis

BACKGROUND

Over the past years, eosinophil infiltration involving the gastrointestinal tract and pancreas leading to eosinophilic pancreatitis, eosinophilic gastroenteritis and hypereosinophilic syndrome has been reported in the literature. We aimed to analyze and compare the features involving patients with eosinophilic pancreatitis and pancreatitis associated with eosinophilic gastroenteritis and to determine if there is a connection between the two disorders or if they in fact meet the diagnostic criteria for hypereosinophilic syndrome.

MATERIAL AND METHODS

The following search was performed in March 2019 on PubMed (MEDLINE) database using the medical terms "pancreatitis", "eosinophilic pancreatitis", "eosinophilic gastroenteritis" and "hypereosinophilic syndrome".

RESULTS

The search revealed 119 publications from 1970 onwards. A total of 83 papers were excluded, and the remaining 36 publications, consisting in case reports and case series, were analyzed. From 45 patients, 20 subjects with eosinophilic gastroenteritis developed pancreatitis, 20/45 had eosinophilic pancreatitis, and 5/45 hypereosinophilic syndrome involving the pancreas. There was no significant difference regarding clinical, laboratory and imaging features between the three groups, despite the multiple theories that explain the association of pancreatic and gastrointestinal eosinophilic infiltration. Although there was a strong resemblance between the three groups, histological evidence of eosinophilic gastrointestinal infiltration guided the treatment towards a less invasive way, while subjects with eosinophilic pancreatitis underwent pancreatic surgery to exclude potentially malignant lesions.

CONCLUSION

Although there are various theories that explain pancreatitis development in patients with eosinophilic gastroenteritis, hypereosinophilia diagnostic work-up should be taken into account in all patients with high number of blood eosinophils, even in those with eosinophilic pancreatitis in order to establish the diagnosis using a minimally invasive approach and to apply an adequate treatment.

Eosinophilic pancreatitis: a rare or unexplored disease entity?

Several case reports show accumulation of eosinophils in pancreatitis patients and term the disease as "eosinophilic pancreatitis (EP)". EP usually presents with a pancreatic tumour and abdominal pain in obstructive jaundice, which is generally not diagnosed until the patient undergoes pancreatic resection. Histologically, EP reveals distinct patterns like diffused, periductal, acinar, and septal inflammatory infiltrates with eosinophils, eosinophilic phlebitis, and localised extreme eosinophilic infiltrates related with pseudocyst formation. EP patients also have elevated serum IgE levels with high eosinophil counts in the pancreas as well as in other organs such as the gastrointestinal tract, which is termed as eosinophilic gastroenteritis. Due to the lack of knowledge based on just a few case reports, it is considered that eosinophilic infiltration is quite rare in the pancreas; therefore, the significance of eosinophils in pancreatitis is not yet established. This review assesses the current understanding of eosinophilic pancreatitis and the important role of eosinophils in promoting pancreatic fibrosis including malignancy.

A rare non-oncological pancreatic mass: eosinophilic pancreatitis diagnosis through EUS-FNA

Background and study aims  Eosinophilic pancreatitis (EP) is a rare etiology of chronic pancreatitis, and few cases have been reported. It is characterized by eosinophilic infiltration of the pancreas and elevated IgE levels. EP is difficult to distinguish from pancreatic cancer based on clinical symptoms and auxiliary exams. We present a case of EP and debate the routine performance of endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) for resectable pancreatic mass.

Role of eosinophils in the initiation and progression of pancreatitis pathogenesis

Eosinophilic pancreatitis (EP) is reported in humans; however, the etiology and role of eosinophils in EP pathogenesis are poorly understood and not well explored. Therefore, it is interesting to examine the role of eosinophils in the initiation and progression of pancreatitis pathogenesis. Accordingly, we performed anti-major basic protein immunostaining, chloroacetate esterase, and Masson's trichrome analyses to detect eosinophils, mast cells, and collagen in the tissue sections of mouse and human pancreas. Induced eosinophils accumulation and degranulation were observed in the tissue sections of human pancreatitis, compared with no eosinophils in the normal pancreatic tissue sections. Similarly, we observed induced tissue eosinophilia along with mast cells and acinar cells atrophy in cerulein-induced mouse model of chronic pancreatitis. Additionally, qPCR and ELISA analyses detected induced transcript and protein levels of proinflammatory and profibrotic cytokines, chemokines like IL 5, IL-18, eotaxin-1, eotaxin-2, TGF-β1, collagen-1, collagen-3, fibronectin, and α-SMA in experimental pancreatitis. Mechanistically, we show that eosinophil-deficient GATA1 and endogenous IL-5-deficient mice were protected from the induction of proinflammatory and profibrotic cytokines, chemokines, tissue eosinophilia, and mast cells in a cerulein-induced murine model of pancreatitis. These human and experimental data indicate that eosinophil accumulation and degranulation may have a critical role in promoting pancreatitis pathogenesis including fibrosis. Taken together, eosinophil tissue accumulation needs appropriate attention to understand and restrict the progression of pancreatitis pathogenesis in humans. NEW & NOTEWORTHY The present study for the first time shows that eosinophils accumulate in the pancreas and promote disease pathogenesis, including fibrosis in earlier reported cerulein-induced experimental models of pancreatitis. Importantly, we show that GATA-1 and IL-5 deficiency protects mice form the induction of eosinophil active chemokines, and profibrotic cytokines, including accumulation of tissue collagen in an experimental model of pancreatitis. Additionally, we state that cerulein-induced chronic pancreatitis is independent of blood eosinophilia.

Food-Induced Acute Pancreatitis

Food allergy, a commonly increasing problem worldwide, defined as an adverse immune response to food. A variety of immune-related effector cells such as mast cells, eosinophils, neutrophils, and T cells are involved in food-related allergic responses categorized as IgE mediated, non-IgE mediated, and mixed (IgE and non-IgE) depending upon underlying immunological mechanisms. The dietary antigens mainly target the gastrointestinal tract including pancreas that gets inflamed due to food allergy and leads acute pancreatitis. Reports indicate several food proteins induce pancreatitis; however, detailed underlying mechanism of food-induced pancreatitis is unexplored. The aim of the review is to understand and update the current scenario of food-induced pancreatitis. A comprehensive literature search of relevant research articles has been performed through PubMed, and articles were chosen based on their relevance to food allergen-mediated pancreatitis. Several cases in the literature indicate that acute pancreatitis has been provoked after the consumption of mustard, milk, egg, banana, fish, and kiwi fruits. Food-induced pancreatitis is an ignored and unexplored area of research. The review highlights the significance of food in the development of pancreatitis and draws the attention of physicians and scientists to consider food allergies as a possible cause for initiation of pancreatitis pathogenesis.

Significance of Eosinophils in Promoting Pancreatic malignancy

Background

Several reports indicate that eosinophils are induced in chronic pancreatitis including patients with pancreatic malignancy. However, significance of eosinophilic pancreatitis (EP) is poorly understood and unexplored.

Aim

Accumulation and degranulation of eosinophils promote pancreatic fibrosis and malignancy.

Method

Human pancreatic tissue biopsy samples including chronic pancreatitis (n=3), malignant (n=4), non-malignant (n=3), and normal (n=3) were used for H&E, anti-MBP staining, anti-tryptase staining, anti-IgE staining and Mason's trichrome staining.

Results

We show induced eosinophils and degranulated eosinophils indicated by the presence of anti-MBP stained extracellular granules in the malignant pancreatic (pancreatic cancer) and non-malignant human pancreatic tissues. A comparable number of eosinophils were observed in non-malignant and malignant pancreatic tissue sections, but the sections differed in degranulated eosinophils and the presence of extracellular granules. Additionally, induced mast cells and tissue-specific IgE positive cells were also detected in the tissue sections of malignant pancreatitis patients compared to non-malignant human pancreatic patients. Tissue-specific IgE induction is critical for the degranulation of eosinophils and mast cells that may lead to increased accumulation of collagen in malignant compared to non-malignant human pancreatic tissue samples. We show a large number of anti-tryptase stained extracellular granules in the tissue sections of malignant pancreatic cancer patients. Both IgE and eosinophil major basic proteins (MBP) are reported for the activation and degranulation of mast cells in tissues.

Conclusion

Taken together, our investigation concludes that eosinophils and mast cells accumulation and degranulation are critical in promoting pancreatitis pathogenesis that may lead to the development of pancreatic fibrosis and malignancy.

Eosinophilic funiculitis initially diagnosed as irreducible inguinal hernia: A case report

BACKGROUND

Most groin masses are first suspected to be groin hernias. More than 80% of bulging groin lesions are reportedly diagnosed as hernias by ultrasonography. Establishment of the correct diagnosis of hernia among all differential diagnoses is not easy. We herein describe a very rare case of groin eosinophilic funiculitis that presented as an irreducible groin hernia.

CASE PRESENTATION

A 59-year-old man presented to our hospital with suspicion of a right groin hernia. He had a 1-week history of a painful right groin tumor. The tumor was about 4 cm without skin redness or warmth, irreducible even in the supine position, and associated with mild tenderness. Enhanced computed tomography showed that the mass seemed to be connected to the intra-abdominal structures. With time, the patient's pain did not increase, the inflammatory response did not worsen, and no ischemic signs were observed by enhanced computed tomography. Therefore, we diagnosed the tumor as an irreducible but not incarcerated hernia and performed elective surgery. Intraoperative examination revealed no hernia sac, and a 4-×3-cm tumor was observed around the spermatic cord. A malignant tumor was not completely ruled out. High orchiectomy was performed after consultation with the urologists. Pathological examination of the tumor showed no malignant features, and the final diagnosis was eosinophilic funiculitis with massive inflammatory changes and eosinophil invasion.

CONCLUSION

Eosinophilic funiculitis is very rare; only three cases have been reported to date. We should always consider unusual causes of groin masses during a surgical approach to hernia-like lesions.

Eosinophilic Pancreatitis: A Rare Cause of Recurrent Acute Pancreatitis

Eosinophilic pancreatitis is a rare form of recurrent acute pancreatitis that demonstrates distinct histologic features, including diffuse, periductal, acinar, and septal inflammatory infiltrates comprised of a pure or predominant population of eosinophils, eosinophilic phlebitis and arteritis, and localized eosinophilic infiltrates with pseudocyst formation. It is associated with elevated serum immunoglobulin E levels, an elevated eosinophil count with systemic manifestations, and eosinophilic infiltrates in other organs of the gastrointestinal tract. We present a case of eosinophilic pancreatitis in a 44-year-old man who was diagnosed after pancreatic resection for recurrent bouts of acute pancreatitis. While the gross and histologic evaluations matched other reported cases of eosinophilic pancreatitis, our patient had only minimal peripheral eosinophilia, no reported history of symptoms related to elevated eosinophilia or immunoglobulin E, and only mild eosinophilic infiltrates in his gallbladder.