Granulocytic Epithelial Lesions Research Articles

Concomitant Autoimmune Pancreatitis Type 2 and Colitis Ulcerosa in a 10 Years-Old Girl

Autoimmune pancreatitis (AIP) has gained significant attention in recent years, with a notable increase in diagnoses due to the diagnostic utility of immunoglobulin G4 (IgG4). Despite the well-known IgG4-related type 1 AIP, a less recognized subtype known as type 2 AIP exists, which is distinct from type 1 AIP and not associated with IgG4. Type 2 AIP presents similar clinical symptoms and imaging findings as type 1 AIP, making its diagnosis challenging without specific serum markers. Tissue confirmation of neutrophilic injury to the pancreatic ducts, known as a granulocytic epithelial lesion, is crucial for diagnosing type 2 AIP. Some cases of type 2 AIP are linked to inflammatory bowel disease, particularly ulcerative colitis, but the exact relationship between the two conditions remains unclear. Questions remain regarding the pathophysiology of type 2 AIP, the possibility of similar granulocytic injuries in other organs, and the characteristics of pediatric cases. In this case report we present a concomitant autoimmune pancreatitis type 2 and colitis ulcerosa in a 10 years-old girl. The patients follow-up showed amelioration of the clinical symptoms due to the present medication.

A case of type 2 autoimmune pancreatitis with spontaneous remission.

A 70-year-old man with epigastric pain was referred to our hospital. Computed tomography and magnetic resonance imaging showed the diffusely enlarged pancreas compared to his normal pancreas 6months prior to presentation. Serum levels of IgG4 and amylase were normal, while C-reactive protein was slightly elevated. Endoscopic ultrasound-guided fine-needle biopsy of the pancreas revealed acinar-ductal metaplasia with neutrophil infiltration and without infiltration of IgG4-positive plasma cells. After the clinical diagnosis of type 2 autoimmune pancreatitis (AIP), his symptoms spontaneously improved without steroid therapy. Three months later, radiological findings showed improved pancreas size and serological findings. The pathological diagnosis of type 2 AIP using endoscopic ultrasound-guided fine-needle biopsy is challenging, particularly for proving granulocyte epithelial lesions. This was a valuable type 2 AIP case in which the images before, at the time of onset, and at the time of spontaneous remission were evaluated.

Recent progress on the treatment of type 1 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 multiorgan involvement. Autoimmune pancreatitis (AIP) is classified into two types: type 1 AIP as a pancreatic manifestation of IgG4-RD and type 2 AIP with granulocytic epithelial lesion and occasional association with ulcerative colitis. Although the pathogenic mechanism still remains unclear, possible multipathogenic factors such as genetic factors, disease-specific or related antigens, and abnormal innate or adaptive immunity may be involved in the development of IgG4-RD. Many immunocytes including M2 macrophages, plasmablasts, B cells, and T-cells (Th2-CD4+T, follicular helper T-cells, and CD4+SLAMF7+cytotoxic T-cells) play important roles in the pathogenesis. Conventional induction and maintenance therapies with glucocorticoid or rituximab are recommended in all symptomatic patients with active IgG4-RD. In those at risk for irreversible damage in any organs, this should be done urgently, regardless of symptoms. As no randomized clinical trials other than glucocorticoid maintenance therapy for type 1 AIP have been performed, the comprehensive management for IgG4-RD has not been established yet. Targeted treatment approaches against the plasmablast to B cell lineage and the CD4+ SLAMF7+ cytotoxic T-cell seem to be promising for the future-directed treatment.

Granulocytic epithelial lesion (GEL) in heterotopic pancreas

BackgroundThe diagnosis of type 2 autoimmune pancreatitis (AIP) is dependent on typical radiologic imaging and the presence of the granulocytic epithelial lesion (GEL), which is characterized by ductal neutrophilic infiltration with or without neutrophilic acinar infiltration. MethodsWe evaluated GEL and related clinicopathologic factors in 165 resected heterotopic pancreata (HPs) [57 gastric (35%), 56 duodenal (34%), 30 omental (18%), and 22 jejunal (13%)] and 29 matched orthotopic pancreata routinely examined during surgery. ResultsGEL was noted in 8% (13/165) of HPs, including ductal epithelial (6/13, 46%) and intraluminal (8/13, 62%) neutrophilic infiltrations. However, there was no GEL in orthotopic pancreata. Abdominal pain was observed in 6 (46%) patients with GEL-positive HPs. GEL was more commonly observed in HPs having symptoms (p = 0.029), a larger size (p = 0.028), and an infiltrative growth pattern (p = 0.006). In addition, periductal lymphoplasmacytic infiltration and fibrosis (both p < 0.001), interstitial fibrosis (p = 0.017), acinar neutrophilic infiltration (p = 0.032), venulitis (p = 0.050), acinar ductal metaplasia (ADM; p = 0.040), and pancreatic intraepithelial neoplasia/intraductal papillary mucinous neoplasms (PanIN/IPMN; p < 0.001) were more commonly seen in HPs with GEL than in those without GEL. Inflammatory bowel disease was present only in one patient with GEL-negative HP. ConclusionsGELs are detected in a subset of HPs without clinical evidence of AIP. Therefore, for the diagnosis of AIP, GEL should be carefully interpreted with the context of other histologic, clinical, and radiologic findings.

Type 2 Autoimmune Pancreatitis: Consensus and Controversies.

Autoimmune pancreatitis (AIP) has attracted much attention in the last two decades, and due to the diagnostic value of immunoglobulin G4 (IgG4), the number of cases diagnosed in clinical practice has markedly increased. However, in contrast to prototypic IgG4-related type 1 AIP, a minor subtype of AIP, referred to as type 2 AIP, is less widely known and has thus not yet been characterized in detail. Type 2 AIP is unrelated to IgG4 and is a completely distinct entity from type 1 AIP. One confusing factor is that the two types of AIP share patterns of clinical presentation (e.g., acute pancreatitis and painless jaundice) and imaging abnormalities (e.g., diffuse or segmental enlargement). Since there are currently no established serum markers, the diagnosis of type 2 AIP is highly challenging and requires the tissue confirmation of neutrophilic injury to the pancreatic ducts, a finding designated as a granulocytic epithelial lesion. Approximately one-third of cases are associated with inflammatory bowel disease, particularly ulcerative colitis; however, the pathological relationship between these two conditions has not yet been clarified. Unanswered questions relate to its pathophysiology, the potential development of a similar granulocytic injury in other organs, and the characteristics of pediatric cases. This review summarizes consensus and controversies surrounding type 2 AIP, with the aim of increasing awareness and highlighting the unmet needs of this underrecognized condition.

Histological features of autoimmune pancreatitis and IgG4-related sclerosing cholangitis with a correlation with imaging findings.

Autoimmune pancreatitis (AIP) is characterized by a tumefactive inflammatory lesion resembling pancreatic carcinoma. Type 1 AIP is a pancreatic manifestation of IgG4-related disease characterized by unique histological features that can be identified on imaging. The capsule-like rim, which is a collar of hypertrophic lesion surrounding the pancreas, consists of lymphoplasmacytic infiltration and fibrosis, and storiform fibrosis is often identified. Hypertrophic lesions of various microscopic architectures such as the ducts, veins (obliterative phlebitis), arteries (periarteritis), and nerves are observed without parenchymal damage. The pancreatic lobules keep their contours, but the acinar cells are diminished and replaced by numerous inflammatory cells. These features provide clues to arrive at a diagnosis of type 1 AIP and to distinguish it from pancreatic carcinoma on imaging. In contrast, type 2 AIP is an epithelium-centered inflammation involving the ducts and lobules. Neutrophilic infiltration in the epithelium and/or lumens (granulocytic epithelial lesion) is a characteristic finding. Lobular swelling due to inflammation is the cause of pancreatic enlargement. IgG4-related sclerosing cholangitis is histologically similar to the hypertrophic ductal lesion in type 1 AIP and characterized by wall thickening due to inflammation and luminal stenosis. The epithelium is intact, which is different from bile duct carcinomas and primary sclerosing cholangitis, the latter of which is characterized by inflammation targeting the epithelium. Although the histological features of type 1 AIP and IgG4-related sclerosing cholangitis are unique, the biopsy diagnosis of these diseases has limitations, which should be recognized by clinicians.

Prevalence of histological features resembling autoimmune pancreatitis in neoplastic pancreas resections.

Types 1 and 2 autoimmune pancreatitis (AIP) can mimic pancreatic neoplasia. Due to the small quantity of tissue in mass-targeted pancreas biopsies, inflammatory features may raise the differential of AIP. However, the frequency of AIP-like histology in neoplastic pancreas is not well characterised. Therefore, the specificity of inflammatory lesions on biopsy with respect to the diagnosis of AIP is uncertain. Neoplastic pancreas resections performed at our institution between 2008 and 2019 were retrospectively reviewed. Features of AIP types 1 and 2 were assessed in the non-neoplastic areas. If features of immunoglobulin (Ig)G4-associated AIP were seen, IgG4 immunohistochemistry was performed. We identified 163 neoplastic pancreas resections. Of these, 34 had one or more types of inflammatory lesions in non-neoplastic pancreatic tissue. Dense lymphoplasmacytic inflammation mimicking type 1 AIP was found in six cases with mild to moderately increased IgG4-positive plasma cells. Neutrophilic infiltrates in small intralobular ducts were found in 20 cases. Mild extralobular ductitis or duct microabscess was found in 10 specimens. Marked neutrophilic duct destruction that resembled granulocytic epithelial lesions was found in 12 cases. Some cases showed multiple features. Approximately 20% of neoplastic pancreas resections showed focal areas that could raise the differential of AIP. More cases showed neutrophilic predominant inflammation as seen in type 2 autoimmune pancreatitis, compared to dense lymphoplasmacytic infiltrates seen in type 1 AIP. Pathologists must be cautious when making a diagnosis of AIP on biopsy tissue based on histological findings alone.

Adolescent Type 2 Autoimmune Pancreatitis

There are two forms of autoimmune pancreatitis (AIP). Type 1 is associated with immunoglobulin G4 (IgG4)-related systemic fibro- inflammatory disease, whereas type 2 AIP is localized to the pancreas and not associated with IgG4. The number of children presenting with type 2 AIP has recently increased. Here, we report a case of type 2 AIP in a 16-year-old adolescent who presented with clinical acute pancreatitis and associated pancreatic masses. He was diagnosed with type 2 AIP based on pancreatic biopsy results showing granulocytic epithelial lesions and supportive radiological imaging and steroid responsiveness.

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.

Clinicopathological and immunological features of follicular pancreatitis - a distinct disease entity characterised by Th17 activation.

Follicular pancreatitis is a recently recognised, distinct clinicopathological entity characterised by the presence of many intrapancreatic lymphoid follicles with reactive germinal centres. However, the clinicopathological and immunological features and causes have not yet been established. We assessed the clinicopathological and immunological profiles of patients with follicular pancreatitis who underwent surgery. This study included three patients with pancreatic masses (age range = 62-75 years; women:men: 1:2). A histopathological study of the resected pancreatic masses revealed abundant lymphoid follicles with reactive germinal centres in both periductal regions and diffusely within the parenchyma. No storiform fibrosis, obliterative phlebitis or granulocytic epithelial lesions were observed. The immunohistochemical examination revealed an IgG4/IgG-positive plasma cell ratio <30% in all patients. Podoplanin (Th17 marker)-expressing lymphocytes were present in the lymphoid follicles of those with follicular pancreatitis, whereas these were absent in normal lymph nodes and in lymphoid follicles of those with IgG4-related autoimmune pancreatitis (AIP). An RNA digital counting assay clearly demonstrated that the expression counts of 20 genes, including dendritic cells and lymphoid follicles markers, and related cytokines were significantly higher in follicular pancreatitis than in IgG4-related AIP (P < 0.01). The expressions of CCR6 and IL23A, which are genes related to Th17, were high. This study shows that follicular pancreatitis is a histopathologically and immunologically distinct disease entity of pancreatitis and is characterised by upregulated Th17 expression.

Autoimmune pancreatitis in children: A single centre experience in diagnosis, management and long term follow up

ObjectivesAutoimmune pancreatitis (AIP) is a rare form of chronic pancreatitis and data is limited in the paediatric population. We aim to describe in detail a cohort of paediatric patients with AIP including their presentation, investigations that led to their diagnosis, management and long-term follow up. MethodsWe retrospectively reviewed the data of 6 patients diagnosed with AIP over an 10-year period. Data including demographics, clinical information, laboratory parameters, serological markers, radiological and histological findings as well as longitudinal follow up were collected. ResultsOut of the six patients, one was diagnosed with definitive Type 1 AIP, two with definitive Type 2 AIP, two with probable Type 2 AIP and one with suspected Type 2 AIP. Median time of follow up was 3.9 years (range 2.6–10.1). 4 patients had pancreatic biopsies with 2 of these patients showing granulocytic epithelial lesions (GELs). 4 patients received steroids and two of them developed ulcerative colitis. Azathioprine was commenced on the patient with Type 1 AIP to help her wean off steroids that caused significant side effects on her. Only two patients developed exocrine insufficiency. ConclusionsThe long term follow up of our cohort of paediatric AIP shows good prognosis. More follow up data on patients with AIP is needed to help further characterize and define the disease.

The role of EUS-guided fine needle aspiration in autoimmune pancreatitis: a single center prospective study

Objectives: Histopathological examination is pivotal in diagnosing autoimmune pancreatitis (AIP). The usefulness of EUS-guided fine needle aspiration (EUS-FNA) in diagnosing AIP remains controversial worldwide. The authors conducted this study to evaluate the efficacy of EUS-FNA for AIP diagnosis using a 22-gauge needle.Methods: Between January 2013 and May 2017, 37 patients had imaging studies suggestive of AIP at Tongji Hospital, and 27 patients of them were enrolled in this study. Tissue specimens acquired through EUS-FNA were analyzed for periductal lymphoplasmacytic infiltrate (LPI), storiform fibrosis (SF), obliterative phlebitis (OP) and immunoglobulin G4 (IgG4)-positive plasma cell counts. Clinical Trials.gov no: TJ-C20121220.Results: LPI and SF were present in 18 (66.67%) and 18 (66.67%) of 27 patients, respectively. Abundant IgG4-positive plasmacyte infiltration >10/high-power field (HPF) was detected in 8 of 27 patients (29.63%). OP and the characteristic findings of idiopathic duct-centric chronic pancreatitis (IDCP) and granulocytic epithelial lesion (GEL) were not detected in this study. According to the International Consensus Diagnostic Criteria (ICDC) for AIP, 5 and 12 of 27 patients were assessed as having level 1 and level 2 histological findings, respectively, suggesting that 17 of 27 patients (62.96%) had lymphoplasmacytic sclerosing pancreatitis (LPSP) based on the ICDC.Conclusions: In 92.6% of patients, pancreatic tissues with >5 HPFs were obtained by EUS-FNA using a 22-G needle. In 63% of patients, histology was evaluated to be ≥ level 2 according to the ICDC. The study indicates that EUS-FNA with a 22-G needle is valuable in the histopathological diagnosis of AIP.

IgG4 Autoimmune Pancreatitis: A G-Force Worth Fighting

Introduction: Autoimmune Pancreatitis (AIP) is a rare but increasingly more recognized cause of chronic pancreatitis. AIP can be divided into Type 1 and Type 2, which are characterized by high amounts of IgG4 Plasma Cells and Granulocytic Epithelial Lesions, respectively. Until recently, most AIP was diagnosed in patients who underwent Pancreaticoduodenectomy due to concern for pancreatic cancer. With the advent of Endoscopic Ultrasound (EUS) and Fine Needle Biopsy (FNB), a less invasive realm for diagnosis and management is now utilized. Here we present a case of a patient with acute pancreatitis and a mysterious pancreatic mass.1304_A.tif Figure 1: CT scan image of tail of pancreas lesion1304_B.tif Figure 2: EUS image of tail of pancreas lesion1304_C.tif Figure 3: Representative H&E sections highlight a dense inflammatory infiltrate composed of lymphocytes, plasma cells and other mixed components, as well as fibrosis within the pancreatic parenchyma; C) IgG+ plasma cells, representative immunohistochemistry section; D) IgG4+ plasma cells, representative immunohistochemistry section.Case report: A 49 year old female presented with abdominal pain and a lipase of 1227. Though the patient had symptoms consistent with acute pancreatitis, she did not have any major risk factors nor familial history. CT Imaging revealed a 4 cm tail of pancreas solid mass. To rule out malignancy, an EUS was performed which showed 3.1 x 3.2 cm hypoechoic and heterogenous mass with poorly formed borders. FNB was successfully done with histopathology revealing storiform fibrosis without granulation, up to 25 IgG4 plasma cells in a high power field, and an IgG4/IgG ratio greater than 40%. The diagnosis of Type 1 AIP was made with a high serum IgG4 level of 109. Ultimately, a corticosteroid taper was initiated which brought resolution of the patient's symptomology. Discussion: Criteria for diagnosis of AIP include 5 distinct entities recognized by the mnemonic HISORt (histology, imaging, serology, organ involvement, and response to therapy). Imaging findings typically show a sausage shape of the pancreas, multifocal strictures, and a positive duct penetrating sign. Tissue histology for Type 1 AIP reveals sheets of plasma cells, storiform fibrosis, and positive IgG4 immunostaining of plasma cells. Upon diagnosis, immunoglobulin deposition within the biliary tree and hepatic parenchyma, as well as multi-organ manifestations of the more broadly termed “IgG4 related diseases” should be taken into clinical consideration. A trucut biopsy was initially indicated since fine needle aspiration (FNA) diagnostic yield was 43%. With the second generation FNB needle the use of trucut biopsy is not needed. First line therapy involves a course of corticosteroids that is typically tapered based on organ responsiveness. More recent case series include depletion of the B cell line with Rituximab for patient's refractory to steroids.

IL-8 Expression in Granulocytic Epithelial Lesions of Idiopathic Duct-centric Pancreatitis (Type 2 Autoimmune Pancreatitis).

Type 2 autoimmune pancreatitis (type 2 AIP) develops in isolation or sometimes in association with ulcerative colitis. Its diagnosis requires the histologic confirmation of granulocytic epithelial lesions (GELs) with no diagnostic biomarker currently available. This study aimed to elucidate the tissue expression of cytokines and their diagnostic value in this condition. In quantitative polymerase chain reaction for multiple cytokines using tissue-derived mRNA, the expression level of interleukin (IL)-8 was markedly higher in type 2 AIP than in type 1 AIP (P<0.001). In immunostaining, IL-8 expression was detected in the ductal/ductular epithelium (11/13; 85%) and infiltrating neutrophils or lymphocytes (12/12; 100%) in type 2 AIP, but was almost entirely negative in type 1 AIP (n=13; both, P<0.001). Although obstructive pancreatitis adjacent to pancreatic cancers (peritumoral pancreatitis) exhibited IL-8 expression in the epithelium (3/12; 25%) and inflammatory cells (10/12; 83%), expression levels were significantly lower than those in type 2 AIP (P<0.001 and 0.020, respectively). The presence of either GELs or IL-8-positive epithelium discriminated type 2 AIP from type 1 AIP or obstructive pancreatitis with 92% sensitivity and 92% to 100% specificity. Furthermore, CD3/IL-8-coexpressing lymphocytes were almost restricted to type 2 AIP. Interestingly, a similar pattern of IL-8 expression was also observed in colonic biopsies of ulcerative colitis. In conclusion, the overexpression of IL-8 may underlie the development of GELs in type 2 AIP, and IL-8 immunostaining or IL-8/CD3 double staining may become an ancillary method for its diagnosis. The similar expression pattern of IL-8 in ulcerative colitis also suggests a pathogenetic link between the 2 conditions.

Diagnosis of Autoimmune Pancreatitis: The Evolution of Diagnostic Criteria for a Rare Disease

Diagnosis of Autoimmune Pancreatitis: The Evolution of Diagnostic Criteria for a Rare Disease

Autoimmune Pancreatitis.

Autoimmune pancreatitis (AIP) is a chronic fibroinflammatory disease of the pancreas that belongs to the spectrum of immunoglobulin G-subclass4-related diseases (IgG4-RD) and typically presents with obstructive jaundice. Idiopathic duct-centric pancreatitis (IDCP) is a closely related but distinct disease that mimics AIP radiologically but manifests clinically most commonly as recurrent acute pancreatitis in young individuals with concurrent inflammatory bowel disease. IgG4 levels are often elevated in AIP and normal in IDCP. Histologically, lymphoplasmacytic acinar inflammation and storiform fibrosis are seen in both. In addition, the histologic hallmark of IDCP is the granulocyte epithelial lesion: intraluminal and intraepithelial neutrophils in medium-sized and small ducts with or without granulocytic acinar inflammation often associated with destruction of ductal architecture. Initial treatment of both AIP and IDCP is with oral corticosteroids for duration of 4weeks followed by a gradual taper. Relapses are common in AIP and relatively uncommon in IDCP, a relatively rare disease for which the natural history is not well understood. For patients with relapsing AIP, treatment with immunomodulators and more recently rituximab has been recommended. Although rare instances of pancreaticobiliary malignancy has been reported in patients with AIP, overall the lifetime risk of developing pancreatic cancer does not appear to be elevated.

Autoimmune pancreatitis type 1 and type 2: A report of two cases

Introduction. Autoimmune pancreatitis is a disease associated with autoimmune mechanisms, clinically manifested mostly as obstructive icterus with or with no entire or partial enlargement of the pancreas, histological lymphoplas-mocytic infiltration, fibrosis or granulocytic epithelial lesions with a favourable therapeutic response to the application of corticosteroids. Type 1 autoimmune pancreatitis is a systemic disease befalling the group of IgG4-related diseases in contrast to type 2 which is specific for pancreas disease. Case report. We presented two cases. The first one was a 64-year-old male patient with autoimmune pancreatitis complaining of abdominal pain, weight loss, weakness and exhaustion. Clinical examination showed a rare IgG4 autoimmune pancreatitis. The second one was a 37-year-old male patient complaining of abdominal pain with diarrhea. The diagnosis made revealed the presence of type 2 autoimmune pancreatitis. Following the diagnosis, immunosuppressive therapy was administered to both patients leading to the improvement of their general condition. Conclusion. Autoimmune pancreatitis is a rare disease, sometimes not easy to differ from pancreatic tumor or bile duct tumor with poor prognosis. Thus, early recognition of the disease is very important, since adequate treatment significantly increases the course and the outcomes of the disease.

From Pathogenesis, Clinical Manifestation, and Diagnosis to Treatment: An Overview on Autoimmune Pancreatitis.

Autoimmune pancreatitis (AIP) is a special type of chronic pancreatitis which is autoimmune mediated. The international consensus diagnostic criteria (ICDC) 2011 proposed two types of AIP: type I is associated with histological pattern of lymphoplasmacytic sclerosing pancreatitis (LPSP), characterized by serum IgG4 elevation, whereas type 2 is named idiopathic duct-centric pancreatitis (IDCP), with granulocytic epithelial lesion (GEL) and immunoglobulin G4 (IgG4) negative. The pathogenic mechanism is unclear now; based on genetic factors, disease specific or related antigens, innate and adaptive immunity may be involved. The most common clinical manifestations of AIP are obstructive jaundice and upper abdominal pain. The diagnosis can be made by a combination of parenchymal and ductal imaging, serum IgG4 concentrations, pancreatic histology, extrapancreatic disease, and glucocorticoid responsiveness according to ICDC 2011. Because of the clinical and imaging similarities with pancreatic cancer, general work-up should be done carefully to exclude pancreatic malignant tumor before empirical trial of glucocorticoid treatment. Glucocorticoid is the most common drug for AIP to induce remission, while there still exists controversy on steroid maintenance and treatment for relapse. Further studies should be done to identify more specific serum biomarkers for AIP, the pathogenic mechanisms, and the treatment for relapse.

The Pathology of IgG4-Related Disease in the Bile Duct and Pancreas.

Immunoglobulin G4-related disease (IgG4-RD) in the pancreatobiliary system manifests as sclerosing cholangitis (SC), hepatic inflammatory pseudotumors, and type 1 autoimmune pancreatitis (AIP). The pathology of IgG4-RD involves an inflammatory process and fibrogenic pathway, the combination of which damages the affected organs. Fibroinflammatory injury is characterized by three microscopic findings: a diffuse lymphoplasmacytic infiltrate rich in IgG4-positive plasma cells, obliterative phlebitis, and storiform fibrosis. Although the diagnosis of IgG4-related pancreatocholangitis is relatively straightforward in surgical specimens, the current clinical requirement is to diagnose patients using biopsy samples, which remains challenging. Histological differential diagnoses include primary SC, follicular cholangitis/pancreatitis, SC with granulocytic epithelial lesions, and type 2 AIP. Although the massive infiltration of IgG4-positive plasma cells is a histological hallmark of IgG4-RD, many other immune cells (e.g., Th2 lymphocytes, regulatory T cells, and M2 macrophages) appear to be strongly involved in orchestral immune reactions.

Reversible sclerosing cholangitis with ulcerative colitis

Sclerosing cholangitis (SC) with granulocytic epithelial lesion (GEL) responds well to immunosuppression therapy. We treated a 42-year-old Japanese female with ulcerative colitis, who was admitted for further evaluation of both an elevated alkaline phosphatase level and dilated intrahepatic bile ducts. A liver biopsy on the fourth hospital day revealed the infiltration of neutrophils into the bile duct epithelium, which was diagnosed as GEL. Because her ulcerative colitis was in an active stage, prednisolone (PSL) therapy was started. After the administration of PSL, laboratory data dramatically decreased. A liver biopsy was performed on the 66th hospital day to confirm the lesion around bile ducts in the portal tract. The infiltration of neutrophils into the bile duct epithelium disappeared after PSL administration, and IgG4-positive plasma cells were not found in the liver. Herein, we report a rare case of GEL-positive SC. The present case provides early evidence of treatment-induced histological changes as well as serial changes in biochemical data during the course of immunosuppression therapy.