Immunoglobulin G4-related hepatobiliary disease

Mimickers of immunoglobulin G4-related hepatobiliary disease on biopsy

With the growing recognition of IgG4-related hepatobiliary disease, establishing a definitive diagnosis relies mainly on a combination of clinical findings, serological markers, and imaging modalities. However, the role of histopathological evaluation remains indispensable, particularly in cases necessitating differential diagnosis or malignancy exclusion. While diagnosing IgG4-related hepatobiliary disease through surgical resection specimens is often straightforward, pathologists encounter substantial challenges when evaluating biopsies. The increasing rarity of surgical interventions exacerbates this due to improved disease recognition and suspicion. Numerous confounding factors, including the absence of the characteristic histologic features, limited tissue sample size, biopsy artifacts, and the limited value of IgG4 counts, further complicate the diagnostic process. Additionally, many other disorders exhibit clinical and histological features that overlap with IgG4-related disease, intensifying the complexity of interpreting biopsy specimens. This article explores the clinical and histomorphologic features of IgG4-related hepatobiliary disease and its potential mimickers. It offers valuable insights for pathologists and clinicians when confronted with biopsy specimens from hepatobiliary organs.

Primary Sclerosing Cholangitis, Small Duct Primary Sclerosing Cholangitis, IgG4-Related Sclerosing Cholangitis, and Ischemic Cholangiopathy: Diagnostic Challenges on Biopsy

Pathologists face many challenges when diagnosing sclerosing biliary lesions on liver biopsy. First, histologic findings tend to be nonspecific with similar to identical features seen in numerous conditions, from benign to outright malignant. In addition, the patchy nature of many of these entities amplifies the inherent limitations of biopsy sampling. The end result often forces pathologists to issue descriptive sign outs that require careful clinical correlation; however, certain clinical, radiologic, and histologic features may be of diagnostic assistance. In this article, we review key elements of four sclerosing biliary processes whose proper identification has significant prognostic and therapeutic implications.

Morphological aspects of small-duct cholangiopathies: A minireview

The biliary system consists of intrahepatic and extrahepatic bile ducts lined by biliary epithelial cells (cholangiocytes). Bile ducts and cholangiocytes are affected by a variety of disorders called cholangiopathies, which differ in aetiology, pathogenesis, and morphology. Classification of cholangiopathies is complex and reflects pathogenic mechanisms (immune-mediated, genetic, drug- and toxin-induced, ischaemic, infectious, neoplastic), predominant morphological patterns of biliary injury (suppurative and non-suppurative cholangitis, cholangiopathy), and specific segments of the biliary tree affected by the disease process. While the involvement of large extrahepatic and intrahepatic bile ducts is typically visualised using radiology imaging, histopathological examination of liver tissue obtained by percutaneous liver biopsy still plays an important role in the diagnosis of cholangiopathies affecting the small intrahepatic bile ducts. To increase the diagnostic yield of a liver biopsy and determine the optimal therapeutic approach, the referring clinician is tasked with interpreting the results of histopathological examination. This requires knowledge and understanding of basic morphological patterns of hepatobiliary injury and an ability to correlate microscopic findings with results obtained by imaging and laboratory methods. This minireview describes the morphological aspects of small-duct cholangiopathies pertaining to the diagnostic process.

Secondary sclerosing cholangitis: mimics of primary sclerosing cholangitis

Sclerosing cholangitis is a chronic cholestatic disease characterized by stricturing, beading, and obliterative fibrosis of the bile ducts. Sclerosing cholangitis is considered primary (PSC) if no underlying etiology is identified or secondary (SSC) if related to another identifiable cause. In this article, we will review the clinical features, pathogenesis, diagnosis, and imaging findings of PSC and SSC, with an emphasis on features that may aid in the distinction of these entities. We will also discuss various etiologies of SSC including recurrent pyogenic cholangitis, other infectious etiologies, ischemic damage, toxic insults, and immunologic, congenital, and miscellaneous causes, highlighting the unique imaging findings and clinical context of each diagnosis.

Case Series of Autoimmune Pancreatitis and IgG4-Related Sclerosing Cholangitis

IgG4-related disease (IgG4-RD) is an emerging immune-mediated disease that can involve any organ. The involvement of the pancreas and biliary tract is the most common and well-studied in the literature. It is characterized by a non-specific presentation, mimicking a malignant process. The goal was to look at the different clinical and paraclinical aspects of this disease, as well as the challenges that come from its management. It was made up of three observations of patients with IgG4-RD involving the biliary tract and pancreas. The first observation concerned intrahepatic biliary cholangitis that was accompanied by porto-mesenteric thrombosis, which was discovered by cholestatic jaundice on the 15th day after an appendectomy, and the patient improved under corticosteroids and anticoagulants. The second observation concerned an acute revelation of the disease. It was an acute attack of chronic pancreatitis of IgG4-RD. The main symptoms were pancreatic pain and exocrine pancreatic insufficiency, and corticosteroid therapy allowed remission. The third observation was related to autoimmune pancreatitis (AIP) and IgG4-related sclerosing cholangitis, revealed by jaundice with cholestasis. The patient acquired corticosteroid resistance and an adverse progression to decompensated cirrhosis, and liver transplantation was indicated. The clinical presentation of IgG4-RD is heterogeneous, as evidenced by our three clinical observations. There are still significant gaps in our understanding, particularly in terms of pathogenesis and factors that influence therapy response. Further observational and interventional research is needed to better manage this disease.

Primary sclerosing cholangitis with moderately elevated serum-IgG4 - characterization and outcome of a distinct variant phenotype

BACKGROUND AND AIMS

Immunoglobulin G4-associated cholangitis (IAC) is characterized by distinctly elevated immunoglobulin G4 in serum (sIgG4) and responds well to corticosteroid therapy. Primary Sclerosing Cholangitis (PSC) is a progressive liver disease without causal treatment options usually not responding to immunosuppression. Increased serum levels of sIgG4 in patients with PSC, that do not meet criteria of IAC, have been reported in 10%-25%. Therefore, we aimed to characterize this subgroup of patients in a retrospective, multicenter study.

METHODS

sIgG4 values of 289 patients with PSC from three German university hospitals were analysed. Patients with elevated sIgG4 levels were identified and further characterized by clinical and biochemical parameters and by cholangiographic presentation. Clinical endpoints, death and liver transplantation were compared between groups. Parameters associated with outcome were identified with Cox regression analysis.

RESULTS

14.5% of patients with PSC showed increased sIgG4 levels (PSC-IgG4), presented with significantly higher (P < .02) albumin, aspartate-aminotransferase, bilirubin and alkaline phosphatase and had a significant lower prevalence of a concomitant autoimmune hepatitis (P = .025). Cholangiogram obtained via ERC showed extrahepatic dominant strictures more often in the PSC-IgG4 subgroup (P = .047). The disease severity models Amsterdam-Oxford-Score (P = .018) and Mayo-Risk-Score (P = .025) predicted lower survival rates for the PSC-IgG4 subgroup. Transplant-free survival after first diagnosis of PSC was shorter in patients with elevated sIgG4 (11.6 vs 15.1 years, P = .001).

CONCLUSION

Patients with PSC and elevated sIgG4 should be considered as a distinct subgroup, characterized by different clinical and cholangiographical features and are associated with an inferior outcome.

The Spectrum of Autoimmune Liver Disorders, Clinical Presentation, and Autoantibodies in Patients From a Tertiary Care Center in Pakistan

Background The autoimmune illnesses that affect the liver include autoimmune hepatitis (AIH), primary biliary cholangitis (PBC), primary sclerosing cholangitis (PSC), and overlap syndrome. In our patients, we aimed to address the complete spectrum of autoimmune liver disorders, clinical presentation, and autoantibodies. Methods The study included all the patients diagnosed with autoimmune liver disorder irrespective of age, gender, and ethnic background presented at the liver clinic of the hospital in the last two years. The diagnosis was based on characteristic clinical and laboratory findings, the presence of one or more characteristic autoantibodies, and/or histological abnormalities. The diagnosis of AIH was further validated by revised International AIH Group criteria using a scoring calculator. The diagnostic criteria for PBC required the presence of chronic elevation of alkaline phosphatase (ALP) with positive antimitochondrial antibody (AMA) or positive PBC-specific anti-nuclear antibodies (ANA) (sp-100, gp-210) tests and/or compatible histology. The patients of AIH-PBC overlap syndrome fulfilled the criteria for AIH in the setting of PBC. Patients having liver involvement in other autoimmune disorders were included in the study. Results The total number of patients was 124; 83 (67%) were females; mean age ± standard error of mean (SEM) was 44.97 ± 1.47 years with a range of 09-84 years. Type-1 AIH was seen in 68 (54.8%) patients, type-2 AIH in 10 (8.1%) patients, PBC in 22 (17.7%) patients, overlap of PBC with AIH in 10 (8.1%) patients, IgG4 disease in four (3.2%) patients, psoriasis-specific immune hepatitis in four (3.2%) patients, celiac disease-related hepatitis in three (2.4%) patients, sarcoidosis in two (1.6%) patients, and ichthyosis-associated hepatitis in one (0.8%) patient. There was a high prevalence of cirrhosis (50%) at the time of presentation; 19% of patients had decompensated liver disease. ANA was positive in 52/68 cases of AIH type-1, but anti-smooth muscle antibody (ASMA) was reactive only in nine cases and anti-soluble liver antigen (SLA) in five cases. There was no female preponderance in type-2 AIH (M:F = 6:4). AMA was reactive in 25 (78%) cases of PBC and overlap syndrome. Antibodies prevalent in PBC (AMA-M2, AMA-M2-3E, sp-100, gp-210, anti-Ro52) were also seen in some cases of AIH, though they did not fulfill the criteria of the overlap syndrome. Conclusion There is an unmet need for the early diagnosis of autoimmune liver diseases and the initiation of appropriate management to prevent complications.

IgG4-related hepatic inflammatory pseudotumour: could MRI suggest the correct diagnosis?

We report a case of a 62-year-old woman, HIV positive, with a 3-week history of jaundice and elevated cholestatic enzymes. Imaging studies displayed intrahepatic biliary dilatation and a central liver lesion. Pathology described lesions of active cholangitis, lymphoplasmacytic infiltration and fibrosis, suggesting a hepatic inflammatory pseudotumour (IPT) IgG4 related. IgG4-related lymphoplasmacytic form of IPT belongs to IgG4-related diseases. We discuss the importance to include IgG4-related hepatic IPT as part of the differential diagnosis of any liver lesion, highlighting potential imaging clues that may help in establishing the correct diagnosis.

Multi-Organ Involvement of Immunoglobulin G4-Related Disease

Immunoglobulin G4-related disease (IgG4-RD) is a fibroinflammatory condition of unknown etiology, with presumed autoimmune mechanisms. It is characterized by high levels of IgG4 and variable clinical manifestations. It can involve one or multiple organs. Herein, we reported the case of a 62-year-old man with three organs involvement. He initially presented with recurrent jaundice. Laboratory analysis revealed cholestasis, high gamma-globulin levels, renal failure, and proteinuria. Abdominal Magnetic Resonance Imaging (MRI) showed segmental strictures of the left intrahepatic bile ducts and the wirsung duct with an increased volume of the pancreas and diffuse bilateral enlargement of the kidneys. Laboratory tests revealed high IgG4 levels (770 mg/dL). Based on the biological and radiological findings, we have suggested the diagnosis of systemic IgG4-related disease involving bile ducts, the pancreas, and probably the kidneys. Renal biopsy revealed lymphoplasmacytic infiltrate and fibrosis, but no IgG4-positive cell. The patient received corticosteroid therapy with a complete resolution of all symptoms and a rapid normalization of all blood tests. The present case underlines the complexity of IgG4-RD because of its variable clinical presentation. The diagnosis is challenging and should be carefully assessed for possible multi-organ involvement.

IgG4-related disease with multiorgan involvement: a case-based review

IgG4-related disease (IgG4-RD) is an immune-mediated multi-organ inflammatory disorder caused by tissue infiltration of lymphocytes with IgG4-secreting plasma cells. Herein, we discuss a case of a patient with IgG4-RD who had involvement of multiple organs: the kidneys, lymph nodes, bone marrow (biopsy performed), lungs, liver, and small intestine (imaging abnormalities). Although several case reports and series of IgG4-RD involving different organ involvement are in the literature, our patient has extensive simultaneous multi-organ involvement. We utilized the four domains (serologic, pathologic, radiologic, and pathologic) as discussed in the new 2019 ACR/EULAR classification criteria to provide a useful framework in considering an alternative tool for IgG4-RD in multi-organ involvement, where biopsy is more invasive and not always accessible. We highlight the findings of each organ involved that increase the likelihood that the patient has IgG4-RD. In our patient, the IgG4-RD classification criteria was fulfilled with total points adding up to 48. Our case meets the classification criteria for IgG4-RD, since at least one organ is involved to meet entry criteria (biopsy proven), no exclusion criteria are present, and the total points are ≥ 20. When such extensive involvement of IgG4-RD occurs, early diagnosis and treatment are recommended to avoid irreversible organ damage and better outcomes.

Differences in Clinical Features and Diagnostic Strategies Between IgG4-Related Autoimmune Cholangitis and Cholangiocarcinoma

IgG4-related autoimmune cholangitis (IgG4-AIC) is often difficult to distinguish from cholangiocarcinoma (CCA). This study aimed to determine a practical clinical strategy for distinguishing between IgG4-AIC and CCA to avoid unnecessary surgical resection. We retrospectively collected and compared the clinicopathological data between IgG4-AIC and CCA patients, including the clinical, serological, and radiological characteristics, to follow up on these patients to investigate the prognosis. Among the 377 patients who received surgical resection for suspecting CCA at the Sun Yat-Sen Memorial Hospital between June 2004 and June 2014, 14 patients were diagnosed as IgG4-AIC through histochemistry after surgery. Immunohistochemistry revealed that IgG4 was up-regulated in the plasma cells of IgG4-AIC tissues in 13 out of 14 patients. The serum CA19-9 level was significantly lower than in the CCA group. Patients with IgG4-AIC can only see slight or no enhancement under the contrast enhancement CT scan, while there are no signs of ring-like or delayed enhancement that is unique to CCA. Thirteen patients were followed up, and the time was 12 to 92 months. Three of them were regularly treated with prednisone after surgery, and original symptoms disappeared. Our study demonstrated that the combination of imaging with serum CA19-9 could improve the preoperative diagnostic value and reduce the rate of unnecessary resection.

Levels of serum IgG subclasses in patients with liver disease: A retrospective study

Viral and alcoholic liver disease, drug induced liver disease (DILD), primary biliary cirrhosis (PBC) and autoimmune hepatitis (AIH) are among the most common liver diseases observed in clinical practice. These diseases lack unique clinical characteristics at the beginning of pathogenesis, which renders specific diagnosis difficult. Immunoglobulin G (IgG) subclasses are the main isoform of antibodies that can be found in the serum that serve important protective roles in immunity. The present study aimed to investigate the serum IgG subclass distribution in patients with the five common liver diseases aforementioned. The present study retrospectively recorded and analyzed the serum IgG subclass levels of different patients, who were grouped according to their clinical diagnosis. Serum IgG subclass levels were measured using immunonephelometric assays. IgG3 levels were found to be significantly increased whereas IgG4 levels were significantly decreased in patients with PBC. In patients with AIH, IgG1 levels were significantly increased. By contrast, IgG1/IgG level ratios in patients with viral liver disease were significantly increased. No clear pattern in the distribution characteristics of IgG subclasses could be observed in cohorts with alcoholic liver disease and DILD in the present study. Additionally, model for end-stage liver disease scores regarding IgG1 in patients with AIH shared a synergistic relationship. Anti-mitochondrial antibody subtype M2 (AMA-M2) and IgG3 in patients with PBC demonstrated a synergistic relationship. These results suggested that IgG subclasses may be used as biomarkers to further the understanding of liver disease, which could allow for early diagnosis.

Pathologic interpretation of endoscopic ultrasound-guided fine needle aspiration cytology/biopsy for pancreatic lesions

Pathologic interpretation of endoscopic ultrasound–guided fine needle aspiration (EUS-FNA) cytology/biopsy specimens is one of the most challenging tasks in cytology and surgical pathology practice, as the procedure often yields minimal amounts of diagnostic material and contains contaminants, such as blood cells and normal intestinal mucosa. EUS-FNA cytology/biopsy will nevertheless become a more popular procedure for evaluation of various pancreatic lesions because they are difficult to approach with conventional endoscopic procedures. Pathologists should understand the structural differences and limitations of EUS-FNA that make pathologic diagnosis difficult. Ancillary tests are available for differential diagnosis of EUS-FNA for various pancreatic lesions. Immunostains are the most commonly used ancillary tests, and pathologists should able to choose the necessary panel for differential diagnosis. Pathologists should review clinical history and radiologic and/or EUS findings before selecting an immunostain panel and making a pathologic diagnosis. In addition, one’s threshold of malignancy should be adjusted according to the appropriate clinical setting to avoid under-evaluation of pathologic diagnoses. Clinico-pathologic correlation is essential in pathologic evaluation of EUS-FNA for pancreatic lesions. Pathologists can reduce errors by correlating clinical and radiologic findings when evaluating EUS-FNA. Some molecular tests can be applied in differential diagnosis of pancreatic neoplastic and cystic lesions. Molecular data should be used as supportive evidence of a specific disease entity, rather than direct evidence, and should be correlated with clinico-pathologic findings to avoid errors in pathologic diagnosis.