Diagnosis of IgG4-related sclerosing cholangitis

IgG4-related sclerosing cholangitis(IgG4-SC)is often associated with autoimmune pancreatitis.However,the diffuse cholangiographic abnormalities observed in IgG4-SC may resemble those observed in primary sclerosing cholangitis(PSC),and the presence of segmental stenosis suggests cholangiocarcinoma(CC).IgG4-SC responds well to steroid therapy,whereas PSC is only effectively treated with liver transplantation and CC requires surgical intervention.Since IgG4-SC was first described,it has become a third distinct clinical entity of sclerosing cholangitis.The aim of this review was to introduce the diagnostic methods for IgG4-SC.IgG4-SC should be carefully diagnosed based on a combination of characteristic clinical,serological,morphological,and histopathological features after cholangiographic classification and targeting of a disease for differential diagnosis.When intrapancreatic stenosis is detected,pancreatic cancer or CC should be ruled out.If multiple intrahepatic stenoses are evident,PSC should be distinguished on the basis of cholangiographic findings and liver biopsy with IgG4 immunostaining.Associated inflammatory bowel disease is suggestive of PSC.If stenosis is demonstrated in the hepatic hilar region,CC should be discriminated by ultrasonography,intraductal ultrasonography,bile duct biopsy,and a higher cutoff serum IgG4 level of 182 mg/dL.     

First case of IgG4-related sclerosing cholangitis associated with autoimmune hemolytic anemia

To our knowledge, patients with immunoglobulin G4-related sclerosing cholangitis (IgG4-SC) associated with autoimmune hemolytic anemia (AIHA) have not been reported previously. Many patients with IgG4-SC have autoimmune pancreatitis (AIP) and respond to steroid treatment. However, isolated cases of IgG4-SC are difficult to diagnose. We describe our experience with a patient who had IgG4-SC without AIP in whom the presence of AIHA led to diagnosis. The patient was a 73-year-old man who was being treated for dementia. Liver dysfunction was diagnosed on blood tests at another hospital. Imaging studies suggested the presence of carcinoma of the hepatic hilus and primary sclerosing cholangitis, but a rapidly progressing anemia developed simultaneously. After the diagnosis of AIHA, steroid treatment was begun, and the biliary stricture improved. IgG4-SC without AIP was thus diagnosed.     

Classification and Diagnostic Criteria for IgG4-Related Sclerosing Cholangitis

IgG4-related sclerosing cholangitis (IgG4-SC) can be classified into four types based on cholangiographic findings and regions of biliary stricture. This cholangiographic classification is useful to differentiate IgG4-SC from mimickers including cholangiocarcinoma, primary sclerosing cholangitis, and pancreatic cancer. Autoimmune pancreatitis (AIP) is a valuable clue for the diagnosis of IgG4-SC because the two are frequently found in association with each other. Two sets of diagnostic criteria for IgG4-SC have been proposed. In Japan, the clinical diagnostic criteria 2020 were recently developed. These clinical diagnostic criteria include narrowing of the intrahepatic and/or extrahepatic bile duct, thickening of the bile duct wall, serological findings, pathological findings, other organ involvement, and effectiveness of steroid therapy. When these criteria are applied, IgG4-SC is initially classified as associated or not associated with AIP, and cholangiographic classification is used for differential diagnosis. In most instances, IgG4-SC can be diagnosed on the basis of clinical diagnostic criteria. However, it is challenging to diagnose isolated IgG4-SC or IgG4-SC not associated with AIP. Here, we review the classification and diagnostic criteria for IgG4-SC, specifically focusing on the clinical diagnostic criteria 2020 and a large IgG4-SC case series from a nationwide survey in Japan.     

Diagnostic procedures for IgG4-related sclerosing cholangitis

Background/purpose

IgG4-related sclerosing cholangitis (IgG4-SC) is one of several diseases associated with autoimmune pancreatitis (AIP). However, diffuse cholangraphic abnormalities seen in association with AIP may resemble those seen in primary sclerosing cholangitis (PSC), and the presence of segmental stenosis suggests cholangiocarcinoma. IgG4-SC responds well to steroid therapy, whereas in contrast, liver transplantation is the only effective therapy for PSC, and surgical intervention is also needed for cholangiocarcinoma. The aim of this review was to establish the diagnostic procedures for IgG4-SC.

Methods

A literature search was conducted, covering English-language articles dealing with IgG4-SC published between 1991 and March 2010. As clinical data on IgG4-SC are limited, the author also took into consideration his own clinical experience with the treatment of IgG4-SC over a period of more than 19 years.

Results

When intrapancreatic stenosis is detected, pancreatic cancer should be ruled out. If multiple intrahepatic stenosis is evident, PSC should be discriminated on the basis of cholangiographic findings and liver biopsy with IgG4 immunostaining. An association with inflammatory bowel disease (IBD) is suggestive of PSC. If stenosis is demonstrated in the hepatic hilar region, cholangiocarcinoma should be discriminated by US, EUS, IDUS, and bile duct biopsy.

Conclusion

For diagnosis of IgG4-SC, coexistence of AIP is the most useful finding. However, the most important consideration for clinicians is to be aware of IgG4-SC when encountering patients with obstructive jaundice.     

Differentiating Immunoglobulin G4-Related Sclerosing Cholangitis from Hilar Cholangiocarcinoma

Background/Aims

Few studies have differentiated immunoglobulin G (IgG) 4-related sclerosing cholangitis (IgG4-SC) from hilar cholangiocarcinoma (CC). Thus, we sought to investigate useful features for differentiating IgG4-SC from hilar CC.

Methods

We retrospectively compared clinical, serological, imaging, and histological features of six patients with IgG4-SC and 42 patients with hilar CC.

Results

In patients with hilar CC, obstructive jaundice was more frequent (p<0.01), serum total bilirubin levels were significantly higher (p<0.05), serum CA19-9 levels were significantly higher (p<0.01), and serum duke pancreatic monoclonal antigen type 2 levels were frequently elevated (p<0.05). However, in patients with IgG4-SC, the serum IgG (p<0.05) and IgG4 (p<0.01) levels were significantly higher and frequently elevated. The pancreas was enlarged in all IgG4-SC patients but only in 17% of hilar CC patients (p<0.01). Salivary and/or lacrimal gland swelling was detected in only 50% of IgG4-SC patients (p<0.01). Endoscopic retrograde cholangiography revealed that the hilar or hepatic duct was completely obstructed in 83% of hilar CC patients (p<0.01). Lower bile duct stenosis, apart from hilar bile duct stenosis, was more frequent in IgG4-SC patients (p<0.01). Bile duct wall thickening in areas without stenosis was more frequent in IgG4-SC patients (p<0.01).

Conclusions

An integrated diagnostic approach based on clinical, serological, imaging, and histological findings is necessary to differentiate IgG4-SC from hilar CC.     

IgG4相关硬化性胆管炎的研究进展

免疫球蛋白G4相关硬化性胆管炎(immunoglob-ulin G4-related sclerosing cholangitis,IgG4-SC)是一种新近认识的以血清IgG4升高、慢性进行性阻塞性黄疸、弥漫性或局限性IgG4阳性浆细胞和淋巴细胞组织浸润、纤维化及闭塞性静脉炎为特征的慢性炎症性疾病,常并发自身免疫性胰腺炎(autoimmune pancreatitis,AIP),其临床、生化及影像学特征与原发性硬化性胆管炎(primary sclerosing cholangitis,PSC)或胆管癌(cholangiocarcinoma,CC)相似.类固醇激素是IgG4-SC的主要治疗手段,而肝移植是PSC唯一的有效治疗方法,CC则需外科手术治疗.因此,IgG4-SC与PSC或CC间的准确鉴别是目前面临的一个十分重要的课题.本文详尽地阐述了免疫球蛋白G4(immunoglobulin G4,IgG4)的特征和功能,IgG4-SC的诊断和治疗,IgG4-SC与AIP、PSC及CC之间关系等研究进展,为IgG4-SC的精确诊断和治疗提供了新的思路.     

IgG4-related Sclerosing Cholangitis Complicated with Cholangiocarcinoma and Detected by Forkhead Box P3 Immunohistochemical Staining

An 80-year-old man was admitted due to biliary stricture with autoimmune pancreatitis. Although radiographical examinations suggested Immunoglobulin G4-related sclerosing cholangitis (IgG4-SC), punched biopsies from the bile duct revealed adenocarcinoma. In the resected specimen, abundant N-terminus of Forkhead box P3 (Foxp3)-positive cells were localized in cholangiocarcinoma (CCA) tissue, while IgG4-positive cells were spread around the entire bile duct. Therefore, the case was diagnosed with IgG4-SC accompanied by CCA, not sporadic CCA. We herein report an informative case wherein IgG4-positive cells were abundant in CCA tissue and Foxp3 immunohistochemical staining allowed us to determine that this case had two entities.     

IgG4相关性硬化性胆管炎100例临床特征分析

目的 由于临床和影像学表现的相似及临床医生认知不足,IgG4相关性硬化性胆管炎(IgG4-SC)常被误诊为原发性硬化性胆管炎(PSC)或胆管癌(CC)等胆汁淤积性疾病,而采取了不必要的手术治疗,因此对IgG4-SC的准确认识非常重要。目前,对IgG4-SC的临床研究比较缺乏,文献多为零星的临床病例报道,缺乏系统总结。我们通过汇总分析国内报道的病例,探讨了IgG4-SC患者的临床特点和误诊原因,以提高对该病的认识和诊断水平。方法 以“IgG4相关性硬化性胆管炎”为关键词在中国知网数据库、万方数据库和维普数据库检索2019年9月前公开发表的文献,并提取相关病例的一般资料、临床表现、实验室检查、影像学表现、病理学特征、误诊情况、治疗和预后等信息进行汇总分析。结果 纳入25篇文献,包括100例患者,男女比例为4∶1,平均发病年龄为(58.8±12.3)岁;最常见的临床表现为黄疸(85%)和腹痛(53%); 94.2%(81/86)患者血清IgG4水平增高,33%患者血清CA19-9升高;影像学表现为胆总管下段狭窄57例,肝门区胆管狭窄伴肝内胆管扩张15例;34例肝组织检查发现胆囊壁/胆管壁纤维组织增生伴大量淋巴细胞和浆细胞浸润,可见闭塞性静脉炎或席纹状硬化;免疫组化检测,15例显示IgG4⁺浆细胞>10/HPF;在100例中,12例因误诊为胆管癌而实施手术治疗,61例应用糖皮质激素治疗,58例(95%)病情缓解。结论 IgG4-SC患者多以梗阻性黄疸和腹痛为主要表现,在临床和影像学表现上与原发性硬化性胆管炎和胆管癌十分相似,需注意鉴别诊断。     

Sclerosing cholangitis associated with autoimmune pancreatitis

Autoimmune pancreatitis is a unique form of chronic pancreatitis characterized by irregular narrowing of the pancreatic duct, pancreatic swelling, and a favorable response to corticosteroids, in which the autoimmune mechanism is postulated in the pathogenesis. High serum immunoglobulin (Ig)G4 concentrations and various types of extrapancreatic involvement are prominent features of this disease. Sclerosing cholangitis is a major extrapancreatic lesion of autoimmune pancreatitis that has been regarded as primary sclerosing cholangitis (PSC) complicating chronic pancreatitis. Because sclerosing cholangitis associated with autoimmune pancreatitis (SC-AIP) also favorably responds to corticosteroid therapy, it should be differentiated from PSC. Useful points regarding the differentiation between SC-AIP and PSC are as follows: (i) PSC occurs in younger and SC-AIP in older individuals; (ii) obstructive jaundice is more frequently seen in SC-AIP; (iii) PSC is complicated with inflammatory bowel disease, whereas SC-AIP is complicated with so called extrapancreatic lesions of AIP; (iv) high serum IgG4 concentrations are frequently seen in SC-AIP; (v) a cholangiogram may differentiate the two conditions to some extent; (vi) abundant IgG4-bearing plasma cell infiltration is seen in SC-AIP; and (vii) steroid therapy is effective for SC-AIP. IgG4-related sclerosing cholangitis without pancreatic lesion may be a metachronous phenotype of SC-AIP, and also should be differentiated from PSC. The pathogenesis of AIP and SC-AIP remains unclear. The complement activation system of the classical pathway may be contributing in some cases.     

Recent Advances in the Concept and Pathogenesis of IgG4-Related Disease in the Hepato-Bilio-Pancreatic System

Recent studies have proposed nomenclatures of type 1 autoimmune pancreatitis (AIP) (IgG4-related pancreatitis), IgG4-related sclerosing cholangitis (IgG4-SC), IgG4-related cholecystitis, and IgG4-related hepatopathy as IgG4-related disease (IgG4-RD) in the hepato-bilio-pancreatic system. In IgG4-related hepatopathy, a novel concept of IgG4-related autoimmune hepatitis (AIH) with the same histopathological features as AIH has been proposed. Among organs involved in IgG4-RD, associations with pancreatic and biliary lesions are most frequently observed, supporting the novel concept of “biliary diseases with pancreatic counterparts.” Targets of type 1 AIP and IgG4-SC may be periductal glands around the bile and pancreatic ducts. Based on genetic backgrounds, innate and acquired immunity, Th2-dominant immune status, regulatory T (Treg) or B cells, and complement activation via a classical pathway may be involved in the development of IgG4-RD. Although the role of IgG4 remains unclear in IgG4-RD, IgG4-production is upregulated by interleukin 10 from Treg cells and by B cell activating factor from monocytes/basophils with stimulation of toll-like receptors/nucleotide-binding oligomerization domain-like receptors. Based on these findings, we have proposed a hypothesis for the development of IgG4-RD in the hepato-bilio-pancreatic system. Further studies are necessary to clarify the pathogenic mechanism of IgG4-RD.     

Sclerosing cholangitis associated with autoimmune pancreatitis differs from primary sclerosing cholangitis

AIM： To clarify the characteristic features of biliary lesions in patients with autoimmune pancreatitis （AIP） and compare them with those of primary sclerosing cholangitis （PSC）.METHODS： The clinicopathological characteristics of 34 patients with sclerosing cholangitis （SC） associated with AIP were compared with those of 4 patients with PSC.RESULTS： SC with AIP occurred predominantly in elderly men. Obstructive jaundice was the most frequent initial symptom in SC with AIP. Only SC patients with AIP had elevated serum IgG4 levels, and sclerosing diseases were more frequent in these patients. SC patients with AIP responded well to steroid therapy. Segmental stenosis of the lower bile duct was observed only in SC patients with AIP, but a beaded and prunedtree appearance was detected only in PSC patients.Dense infiltration of IgG4-positive plasma cells was detected in the bile duct wall and the periportal area, as well as in the pancreas, of SC patients with AIP.CONCLUSION： SC with AIP is distinctly different from PSC. The two diseases can be discriminated based on cholangiopancreatographic findings and serum IgG4 levels.     

Clinical clues to suspicion of IgG4-associated sclerosing cholangitis disguised as primary sclerosing cholangitis or hilar cholangiocarcinoma

Background and Aim: This study aimed to determine the clinical characteristics of immunoglobulin G4 (IgG4)‐associated sclerosing cholangitis (ISC) and provide clinical clues differentiating ISC from primary sclerosing cholangitis (PSC) or hilar cholangiocarcinoma (CCC). Methods: Sixteen patients with ISC manifesting as hilar/intrahepatic strictures were analyzed for clinical characteristics and compared with patients with PSC and hilar CCC as disease controls for histology and serum IgG4 levels. Results: Distinguished biliary imaging findings of ISC included multifocal biliary tree involvement (n = 14), concentric bile duct thickening with preserved luminal patency (n = 13), and relatively mild proximal dilatation, despite prominent bile duct thickening (n = 11). Serum IgG4 levels were elevated in 12 patients (75%), but not in any of the 25 patients with hilar CCC. Ten patients (63%) had a past or concurrent history of autoimmune pancreatitis (AIP). The significant infiltration of IgG4‐positive cells was observed with endobiliary or liver biopsy in 11 of 16 patients (69%) with ISC, but not in any patients with PSC or hilar CCC. Extrabiliary organ involvement, including sialadenitis, inflammatory pseudotumor of the liver and kidney, and retroperitoneal fibrosis, was present in seven patients. Marked improvement of biliary strictures and/or extrabiliary involvement was observed in all ISC patients after steroid therapy. Conclusions: ISC should be considered in the differential diagnosis of hilar/intrahepatic biliary strictures. Past or concurrent AIP or extrabiliary organ involvement strongly suggests the possibility of ISC. Significant infiltration of IgG4‐positive cells on endobiliary or liver biopsy specimens, and/or elevated serum IgG4 levels, highly support the diagnosis of ISC and provide the rationale for steroid therapy.     

Autoimmune pancreatitis and cholangitis

Autoimmune pancreatitis(AIP) is part of a systemic fibrosclerotic process characterized by lymphoplasmacytic infiltrate with immunoglobulin G subtype-4(Ig G4) positive cells. It characteristically presents with biliary obstruction due to mass-like swelling of the pancreas. Frequently AIP is accompanied by extra-pancreaticmanifestations including retroperitoneal fibrosis, thyroid disease, and salivary gland involvement. Auto-antibodies, hypergammaglobulemia, and prompt resolution of pancreatic and extrapancreatic findings with steroids signify its autoimmune nature. Refractory cases are responsive to immunomodulators and rituximab. Involvement of the biliary tree, termed IgG 4 associated cholangiopathy, mimics primary sclerosing cholangitis and is challenging to manage. High IgG 4 levels and swelling of the pancreas with a diminutive pancreatic duct are suggestive of autoimmune pancreatitis. Given similarities in presentation but radical differences in management and outcome, differentiation from pancreatic malignancy is of paramount importance. There is controversy regarding the optimal diagnostic criterion and steroid trials to make the diagnosis. Additionally, the retroperitoneal location of the pancreas and requirement for histologic sampling, makes tissue acquisition challenging. Recently, a second type of autoimmune pancreatitis has been recognized with similar clinical presentation and steroid response though different histology, serologic, and extrapancreatic findings.     

Autoimmune pancreatitis associated with a large pancreatic pseudocyst that disappeared after corticosteroid therapy: a case report and literature review

A 51-year-old woman was admitted to our department because of upper abdominal pain. The serum IgG4 concentration was elevated, and abdominal computed tomography revealed diffuse enlargement of the pancreas associated with a large cyst, measuring 8 cm in diameter. Endoscopic retrograde cholangiopancreatography revealed narrowing of the main pancreatic duct (from the body to the tail), narrowing of the intrapancreatic bile duct, and dilatation of the bile ducts. The patient was given a diagnosis of autoimmune pancreatitis (AIP) associated with a pancreatic pseudocyst and intrapancreatic bile duct stenosis. Oral steroid therapy resulted in reduced pancreatic swelling, complete disappearance of the pancreatic cyst, and an improvement in biliary stenosis. AIP is rarely associated with pancreatic cyst, and only 13 cases, including ours, have been reported to date. In our patient, intense inflammation apparently led to cyst formation in association with AIP, which responded remarkably to corticosteroid therapy. Correct diagnosis of AIP associated with a pancreatic pseudocyst might save patients from undergoing unnecessary endoscopic and surgical procedures.     

Localized intrahepatic IgG4-related sclerosing cholangitis (IgG4-SC) as an additional type of IgG4-SC: a systematic analysis of 12 cases

Objectives: IgG4-related sclerosing cholangitis (IgG4-SC), a recently defined disease entity, has been classified into four types based on the stricture regions revealed by cholangiography. However, localized intrahepatic IgG4-SC is not included into the classification. This study aimed to analyze and characterize localized intrahepatic IgG4-SC and justify the inclusion of this type into the classification.

Methods: PubMed and Embase were searched for studies published from March 2001 to June 2017 reporting localized intrahepatic IgG4-SC. Data were obtained and analyzed from the included articles.

Results: Twelve cases of localized intrahepatic IgG4-SC were included. All patients were adults with the median age of 73 years (range 46–78), and had a male preponderance (88.9%). The most common clinical presentation was obstructive jaundice (50%), abdominal pain (25%) and absence of symptoms (25%). On imaging and macroscopically, localized intrahepatic IgG4-SC presented with three subtypes, i.e., mass-forming (n?=?6, 50%), stricture (n?=?5, 41.7%) and periductal infiltrating (n?=?1, 8.3%) subtypes. Among the eight cases with diagnoses reported, six patients were misdiagnosed as intrahepatic cholangiocarcinoma; one was diagnosed as hepatic mass and one as IgG4-SC before biopsy or operation. Information on treatment was available on 10 cases; eight underwent surgical resection, one received steroid treatment alone and one underwent endoscopic biliary drainage. No relapse was noted in patients with surgical resection during a period of followed up.

Conclusions: The localized intrahepatic IgG4-SC presents with mass-forming, stricture and periductal infiltrating subtypes, and should be recognized as an additional type of IgG4-SC according to the cholangiographic classification or anatomic site.     

Coexisting Type 1 Autoimmune Pancreatitis and Mixed-type Intraductal Papillary Mucinous Neoplasm

An 84-year-old man was referred to our hospital for a cystic lesion of the pancreatic head, swelling of the pancreatic tail and hilar biliary stricture, resulting in elevated liver enzyme levels. We suspected branch duct-type intraductal papillary mucinous neoplasm (IPMN) and type I autoimmune pancreatitis (AIP) associated with sclerosing cholangitis because of the high serum IgG4 levels. The main pancreatic duct on the tail side of the AIP lesion was moderately dilated. Although the biliary stricture and pancreatic swelling improved after prednisolone treatment, the pancreatic enzyme levels increased rapidly. The entire main pancreatic duct exhibited remarkable dilatation, which led to the diagnosis of mixed-type IPMN. The clinical characteristics of IPMN in the main pancreatic duct appear to have been initially masked by AIP.     

Inflammatory bowel disease of primary sclerosing cholangitis: A distinct entity?

This is a review of the characteristic findings of inflammatory bowel disease(IBD)associated with primary sclerosing cholangitis(PSC)and their usefulness in the diagnosis of sclerosing cholangitis.PSC is a chronic inflammatory disease characterized by idiopathic fibrous obstruction and is frequently associated with IBD.IBDassociated with PSC(PSC-IBD)shows an increased incidence of pancolitis,mild symptoms,and colorectal malignancy.Although an increased incidence of pancolitis is a characteristic finding,some cases are endoscopically diagnosed as right-sided ulcerative colitis.Pathological studies have revealed that inflammation occurs more frequently in the right colon than the left colon.The frequency of rectal sparing and backwash ileitis should be investigated in a future study based on the same definition.The cholangiographic findings of immunoglobulin G4-related sclerosing cholangitis(IgG4-SC)are similar to those of PSC.The rare association between IBD and IgG4-SC and the unique characteristics of PSC-IBD are useful findings for distinguishing PSC from IgG4-SC.     

Mass‐forming type 1 autoimmune pancreatitis mimicking pancreatic cancer

We reported three cases of mass‐forming type 1 autoimmune pancreatitis (AIP) that were preoperatively suspected to be pancreatic cancer, and reviewed their clinicopathological features. Radiological findings in the patients revealed hypoattenuating masses in the early phase or a stricture of the main pancreatic duct with upstream dilatation, which was consistent with the diagnosis of pancreatic cancer. Histopathologically, the lesions were well demarcated and met all diagnostic criteria for immunoglobulin G4 (IgG4)‐related AIP, including the presence of periductal lymphoplasmacytic infiltration, obliterative phlebitis, storiform fibrosis and abundant IgG4‐positive plasma cells. However, the adjacent uninvolved pancreatic duct and lobular structures were well preserved. And in all patients, none or some of the aforementioned characteristics were observed. We suggest that some cases of focal AIP may progress to more severe grades and exhibit mass formation, although remaining localized. These focal cases of AIP are difficult to distinguish from pancreatic cancer. To our knowledge, this report is the first to present a histopathological comparison of mass‐forming AIP with the adjacent uninvolved pancreatic tissues.     

Role of endoscopy in the diagnosis of autoimmune pancreatitis and immunoglobulin G4‐related sclerosing cholangitis

Autoimmune pancreatitis (AIP) must be differentiated from pancreatic carcinoma, and immunoglobulin (Ig)G4‐related sclerosing cholangitis (SC) from cholangiocarcinoma and primary sclerosing cholangitis (PSC). Pancreatographic findings such as a long narrowing of the main pancreatic duct, lack of upstream dilatation, skipped narrowed lesions, and side branches arising from the narrowed portion suggest AIP rather than pancreatic carcinoma. Cholangiographic findings for PSC, including band‐like stricture, beaded or pruned‐tree appearance, or diverticulum‐like outpouching are rarely observed in IgG4‐SC patients, whereas dilatation after a long stricture of the bile duct is common in IgG4‐SC. Transpapillary biopsy for bile duct stricture is useful to rule out cholangiocarcinoma and to support the diagnosis of IgG4‐SC with IgG4‐immunostaining. IgG4‐immunostaining of biopsy specimens from the major papilla advances a diagnosis of AIP. Contrast‐enhanced endoscopic ultrasonography (EUS) and EUS elastography have the potential to predict the histological nature of the lesions. Intraductal ultrasonographic finding of wall thickening in the non‐stenotic bile duct on cholangiography is useful for distinguishing IgG4‐SC from cholangiocarcinoma. Endoscopic ultrasound‐guided fine‐needle aspiration (EUS‐FNA) is widely used to exclude pancreatic carcinoma. To obtain adequate tissue samples for the histological diagnosis of AIP, EUS‐Tru‐cut biopsy or EUS‐FNA using a 19‐gauge needle is recommended, but EUS‐FNA with a 22‐gauge needle can also provide sufficient histological samples with careful sample processing after collection and rapid motion of the FNA needles within the pancreas. Validation of endoscopic imaging criteria and new techniques or devices to increase the diagnostic yield of endoscopic tissue sampling should be developed.     

Pathology and immunopathology of immunoglobulin G4-related sclerosing cholangitis: The latest addition to the sclerosing cholangitis family

Sclerosing cholangitis is heterogeneous in its etiopathogenesis. Recently, sclerosing cholangitis showing abundant immunoglobulin (Ig)G4+ plasma cell infiltration was added to the sclerosing cholangitis group. This form was frequently associated with sclerosing pancreatitis (autoimmune pancreatitis) and also occasionally with other diseases such as chronic sclerosing sialadenitis, all of which falls within IgG4-related sclerosing disease. Herein, this new member, called IgG4-related sclerosing cholangitis (IgG4-SC), is reviewed. IgG4-SC shows grossly medullary and fleshy lesions along the biliary tree, and histologically marked lymphoplasmacytic infiltration with extensive fibrosis, and obliterative phlebitis, sharing histopathological features with sclerosing pancreatitis. Peribiliary glands are also severely affected. Interestingly, hepatic inflammatory pseudotumor (HIP) is not infrequently associated with IgG4-SC, and is thought as a local exaggeration of IgG4-SC. Immunohistochemically, many IgG4+ plasma cells and CD4+/CD25+ regulatory T cells are found around the affected bile ducts and portal tracts. Incontrast, these cells are scarce in the affected bile ducts of primary sclerosing cholangitis (PSC), a prototype of sclerosing cholangitis. Biliary lining epithelia are relatively spared in IgG4-SC in comparison with those of PSC showing degeneration and ulceration. In some cases of IgG4-SC, IgG4+ plasma cells are also found considerably in small portal tracts, so needle liver biopsy is useful for the diagnosis of IgG4-SC. Therapeutically, IgG4-SC responds well to steroid therapy, while such character is not reported in PSC. Taken together, IgG4-SC may be etiologically different from PSC, and immunopathological processes relating to IgG4 and regulatory T cells may be involved in the pathogenesis of IgG4-SC. Further studies are needed to clarify the etiopathogenesis of IgG4-SC and its related disorders.