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Objectives: Patients diagnosed with primary sclerosing cholangitis (PSC) but with characteristics of immunoglobulin G4 (IgG4)-associated cholangitis (IAC) have been described. IAC often presents with biliary IgG4-positive plasma cell (IgG4+ PC) infiltration and responds to corticosteroids. In PSC, the frequencies or implications of biliary IgG4+ PC are unknown. We aimed to characterize the phenomenon of biliary IgG4+ PC in patients with an established PSC diagnosis., Methods: Bile duct biopsies from 191 surveillance or therapeutic endoscopic retrograde cholangiography of 58 PSC patients were retrospectively analyzed for IgG4+ PC infiltration. Patients with ≥10 IgG4+ PC per high-power field (HPF) were identified and characterized by clinical parameters, including serum IgG4 and cholangiographic presentations., Results: Altogether 39.7% of the PSC patients showed ≥10 IgG4+ PC/HPF in bile duct biopsies. Patients with biliary IgG4+ PC infiltration were significantly younger at diagnosis of PSC (P = 0.023). There was no association between biliary IgG4+ PC infiltration and transplant-free survival (P = 0.618). Patients with IgG4+ PC infiltration in bile duct biopsies showed significantly higher baseline (P = 0.002) and maximum (P = 0.001) serum IgG4 compared to those without. Biliary IgG4+ PC infiltration was associated with high-grade bile duct strictures (P = 0.05). IgG4-positive plasma cell infiltrations were found multifocally in 72.7% of this subgroup of PSC patients., Conclusions: IgG4+ PC ≥10/HPF can be found abundantly in bile duct biopsies in PSC. Histological findings correlated with serum IgG4, age, and high-grade bile duct strictures. IgG4+ PC was located multifocally, hinting at a systemic biliary phenotype., (© 2024 The Author(s). Journal of Digestive Diseases published by Chinese Medical Association Shanghai Branch, Chinese Society of Gastroenterology, Renji Hospital Affiliated to Shanghai Jiaotong University School of Medicine and John Wiley & Sons Australia, Ltd.)

Backgruound: Hashimoto thyroiditis (HT) is suspected to correlate with papillary thyroid carcinoma (PTC) development. While some HT cases exhibit histologic features of immunoglobulin G4 (IgG4)-related disease, the relationship of HT with PTC progression remains unestablished., Methods: This cross-sectional study included 426 adult patients with PTC (≥1 cm) undergoing thyroidectomy at an academic thyroid center. HT was identified based on its typical histologic features. IgG4 and IgG immunohistochemistry were performed. Wholeslide images of immunostained slides were digitalized. Positive plasma cells per 2 mm2 were counted using QuPath and a pre-trained deep learning model. The primary outcome was tumor structural recurrence post-surgery., Results: Among the 426 PTC patients, 79 were diagnosed with HT. With a 40% IgG4 positive/IgG plasma cell ratio as the threshold for diagnosing IgG4-related disease, a cutoff value of >150 IgG4 positive plasma cells per 2 mm2 was established. According to this criterion, 53% (43/79) of HT patients were classified as IgG4-related. The IgG4-related HT subgroup presented a more advanced cancer stage than the IgG4-non-related HT group (P=0.038). The median observation period was 109 months (range, 6 to 142). Initial assessment revealed 43 recurrence cases. Recurrence-free survival periods showed significant (P=0.023) differences, with patients with IgG4 non-related HT showing the longest period, followed by patients without HT and those with IgG4-related HT., Conclusion: This study effectively stratified recurrence risk in PTC patients based on HT status and IgG4-related subtypes. These findings may contribute to better-informed treatment decisions and patient care strategies.

Immunoglobulin G4-related disease (IgG4-RD) is a fibroinflammatory condition characterized by chronic activation of the immune system and a tendency to form tumorous lesions. IgG4-RD is frequently characterized by the presence of tumor-like masses affecting multiple organs and is easily mistaken for a malignant neoplasm. However, IgG4-RD affecting the appendix is extremely rare, with only seven cases reported previously. We report the case of a woman in her early 60s who presented with insidious abdominal pain and radiological findings mimicking appendiceal neoplasms. After diagnosing appendiceal neoplasms, surgery was performed. The patient had a serum IgG4 concentration of <1.35 g/L, which did not satisfy one of the three revised comprehensive diagnostic criteria for IgG4-RD. A pathological examination was conducted, and the patient was diagnosed with appendiceal IgG4-RD. To the best of our knowledge, there have been no previously reported cases of IgG4-RD affecting the appendix in patients with low serum IgG4 concentrations. This report may prove beneficial for the future understanding of IgG4-RD and for the revision of diagnostic and treatment strategies., Competing Interests: Declaration of conflicting interestThe authors declare that there is no conflict of interest.

Background: Constrictive pericarditis remains a problematic diagnosis and a thorough investigation is critical. Among possible aetiologies, immunoglobulin-G4 (IgG4)-related pericardial disease is an unusual cause of pericardial constriction. We report a challenging diagnostic case of pericardial constriction due to IgG4-related disease., Case Presentation: A 68-year old male with a history of inferior myocardial infarction with right ventricle (RV) involvement was thrice-hospitalized due to marked ascites and peripheral oedema. Systemic congestion was initially attributed to RV dysfunction due to previous infarction. Yet, at the final admission, a re-assessment echocardiogram followed by cardiac computed tomography, magnetic resonance and right heart catheterization raised a possible diagnosis of constrictive pericarditis with a finding of abnormal pulmonary venous return. Patient therefore underwent pericardiectomy and surgical correction of pulmonary venous return. Pericardium histology revealed an IgG4-related pericardial constriction. Patient was later discharged on corticosteroids with marked symptomatic improvement., Conclusion: IgG4-related disease remains a rare cause of pericardium constriction while also presenting a challenging diagnosis in everyday clinical practice. This case exemplifies the difficulties faced by clinicians when reviewing a possible case of constrictive pericarditis, while highlighting the importance of a multimodality assessment., (© 2022. The Author(s).)

Introduction: Immunoglobulin G subclass measurements are important for the diagnostic work-up of immunodeficiencies and immunoglobulin G4 (IgG4) related diseases. It is currently unknown whether a single sampling is truly representative for an individual's IgG subclass concentrations. This study aimed to investigate whether IgG and IgG subclass concentrations in healthy individuals are stable over time., Method: With a span of median 42 weeks, four samples from each of 54 (34M, 20F) healthy adult volunteers (24-66 years) were analyzed for IgG and IgG1-4 using turbidimetry. Concentrations were compared within and between individuals., Results: IgG and IgG subclass concentrations followed either a normal (IgG, IgG1, and IgG3) or log normal (IgG2 and IgG4) distribution. Immunoglobulin 4 demonstrated by far the widest range of concentrations between individuals (670-fold: 0.004-2.68 g/L). Immunoglobulin G subclass variations within individuals were expressed as pooled standard deviations (PSD). These ranged from 0.056 (IgG4) to 0.955 g/L (IgG) and correlated with mean concentration of IgG or the particular IgG subclass. As a consequence, the relative PSDs (i.e., PSD divided by mean IgG or IgG subclass concentration) fell within a narrow range: 5.82%-10.1%. Based on these numbers, the 95%-upper one-sided confidence limits for intraindividual IgG and IgG subclass variation was calculated to range from 9.82% (IgG2) to 16.9% (IgG4)., Conclusion: The study documents that IgG or IgG subclass concentrations within healthy individuals are very stable over at least 42 weeks. The expected variation for IgG4 concentrations at a 95% confidence level does not exceed ±16.9%., (© 2021 The Authors. Immunity, Inflammation and Disease published by John Wiley & Sons Ltd.)

Background: The diagnosis of autoimmune pancreatitis (AIP) remains challenging, especially when serum IgG4 is normal or imaging features are indeterminate. We performed a systematic review and meta-analysis to evaluate the performance of IgG4 immunostaining of pancreatic, biliary, and ampullary tissues as a diagnostic aid for AIP., Methods: A comprehensive literature search of the PubMed, EMBASE, and Ovid MEDLINE databases was conducted until February 2020. The methodological quality of each study was assessed according to the Quality Assessment of Diagnostic Accuracy Studies checklist. A random-effects model was used to summarize the diagnostic odds ratio and other measures of accuracy., Results: The meta-analysis included 20 studies comprising 346 patients with AIP and 590 patients with other pancreatobiliary diseases, including 371 pancreatobiliary malignancies. The summary estimates for tissue IgG4 in discriminating AIP and controls were as follows: diagnostic odds ratio 38.86 (95% confidence interval (CI), 18.70-80.75); sensitivity 0.64 (95% CI, 0.59-0.69); specificity 0.93 (95% CI, 0.91-0.95). The area under the curve was 0.939 for tissue IgG4 in discriminating AIP and controls. Subgroup analysis revealed no significant difference in diagnostic accuracy according to control groups (pancreatobiliary cancer versus other chronic pancreatitis) and sampling site (pancreas versus bile duct/ampulla)., Conclusions: Current data demonstrate that IgG4 immunostaining of pancreatic, biliary, and ampullary tissue has a high specificity but moderate sensitivity for diagnosing AIP. IgG4 immunostaining may be useful in supporting a diagnosis of AIP when AIP is clinically suspected, but a combination of imaging and serology does not provide a conclusive diagnosis., Competing Interests: Declaration of competing interest The authors declare that they have no conflict of interest., (Copyright © 2020 IAP and EPC. Published by Elsevier B.V. All rights reserved.)

Background: Immunoglobulin G4-related lung disease (IgG4-RLD) is the pulmonary manifestation of a systemic fibroinflammatory disease characterized by lymphoplasmacytic infiltration with an abundance of IgG4-positive plasma cells. Long-term clinical course and outcomes of IgG4-RLD remain unclear. We aimed to identify clinical characteristics, treatment outcomes, and longitudinal pulmonary function changes in patients with IgG4-RLD according to the radiologic classification., Methods: Chest computed tomography findings of 37 subjects were classified into five subtypes: solid nodular, bronchovascular, alveolar interstitial, round ground glass opacity, and alveolar consolidative. Radiologic treatment outcomes and longitudinal pulmonary function changes were compared among the different radiologic subtypes., Results: The mean age of the subjects was 55.6 years, and 78.4% were male. Among the five radiologic subtypes, alveolar consolidative and solid nodular type were most common, accounting for approximately 29.7% each of the total cases. Prednisone with or without azathioprine was administered to 31 patients (median treatment duration 14 months). In the treated patients, serial images showed complete response or partial response in 77.4%. However, relapse was documented in 25.0% of those who showed complete or partial response. In patients whose longitudinal lung function data were available (n = 20), the lung function was found to be stable during follow-up. Alveolar consolidative type showed the highest complete response rate, whereas alveolar interstitial type showed the lowest response rate, either complete or partial., Conclusions: Most patients showed a favorable outcome with regards to radiologic improvement and maintenance of pulmonary function; however, the response differed according to the radiologic subtype.

Background: Immunoglobulin G4-related disease (IgG4-RD) is an immune mediated fibro inflammatory condition characterized by abundant IgG4-positive (IgG4+) plasma cell infiltrated lesions and elevated serum IgG4 concentrations. Tubulointerstitial nephritis and glomerular lesions are the most common renal IgG4-RDs. However, solitary mass lesion is rarely observed in renal IgG4-RD., Materials and Methods: We reported a 55-year-old male patient with a space-occupying lesion in the right kidney detected during a routine ultrasound medical examination. Computed tomography indicated a 20 mm × 15 mm × 18 mm mass located at the lower pole of the right kidney. Both T1-weighted imaging and T2-weighted imaging magnetic resonance imaging scans showed a hypointense mass. Diffusion-weighted imaging (b value = 800) showed slightly hyperintensity., Results: The lesion was diagnosed as renal cell carcinoma clinically based on the laboratory and radiological findings and treated with laparoscopic resection. However, the postoperative histological examination results indicated the lesion IgG4-RD of the kidney., Conclusion: We should consider pseudotumor-like IgG4-RD as a differential diagnosis for solitary renal lesion although the incidence is low., Competing Interests: None

Patients with immunoglobulin G4-related thoracic aortitis often have nonspecific symptoms, but pain in the chest or back is common. The rate of misdiagnosis of immunoglobulin G4-related thoracic aortitis is high, which may lead to mistreatment in extreme cases. A correct diagnosis should be based on comprehensive medical imaging, pathology, and laboratory and immunohistochemical results. Most patients' condition can be significantly improved using conservative or surgical treatment.

Immunoglobuline G4-related disease (IgG4-RD) is a systemic disease that can involve virtually any organs including the biliary tract and liver. The biliary tract involvement of IgG4-RD is known as IgG4-sclerosing cholangitis (IgG4-SC) and may or may not present with an inflammatory pseudotumor. Large bile ducts such as extrahepatic, hilar, and perihilar ducts are typically affected and demonstrate marked bile duct wall thickening and develop strictures. Histologically, the involved ducts show transmural dense lymphoplasmacytic infiltrates with storiform fibrosis extending into peribiliary glands and periductal soft tissue. The luminal epithelium is usually preserved. Tissue eosinophilia and obliterative phlebitis are also frequently noted. Liver biopsy findings of IgG4-SC are heterogeneous and rather nonspecific, but two features specific to IgG4-SC have been described: >10 IgG4-positive plasma cell/HPF and small portal-based fibroinflammatory nodules. Secondary changes, due to downstream bile duct obstruction are often appreciated. When considering the differential diagnosis, primary sclerosing cholangitis and cholangiocarcinoma are great clinical and histologic mimics of IgG4-SC. Liver involvement in IgG4-RD has not been well characterized and includes IgG4-hepatopathy and IgG4-related autoimmune hepatitis (AIH). IgG4-hepatopathy is a generic term covering hepatic lesions related to IgG4-RD and /or IgG4-SC. It includes primary liver parenchymal changes inherent to IgG4-RD, liver parenchymal involvement of IgG4-SC, and secondary changes related to IgG4-SC. IgG4-related AIH is characterized by clinical and histologic features of classical AIH but with prominent (>10/HPF) IgG4-positive plasma cells. It is unclear whether this represents a hepatic manifestation of IgG4-RD or a subset of AIH with increased IgG4-positive plasma cells at the present time. Synchronous or metachronous involvement of other organs, offers a clue to make this distinction. IgG4 immunohistochemistry has an important role in diagnosing IgG4-RD. But the diagnosis cannot be made solely based on the number of IgG4-positive plasma cells, and results need to be interpreted with caution as increased IgG4-positive plasma cells can be seen in other inflammatory conditions or even in malignancy., (Copyright © 2019. Published by Elsevier Inc.)

We present an asymptomatic case of a 79-year-old Japanese man who had a 6 mm colonic inflammatory polyp with numerous immunoglobulin G4 (IgG4)-positive plasma cells. No symptoms or abnormal laboratory data, such as changes in serum IgG4 levels, were found at the time of diagnosis or during the 1 year of follow-up thereafter. Additionally, no diffuse/localized swelling or masses were found in organs, except for colonic polyps, by abdominal computed tomography 1 year prior to the polypectomy. Inflammatory myofibroblastic tumor was unlikely from the lack of spindle cell proliferation and ALK immunoreactivity. This is the first case of this colonic polyp in an asymptomatic person. This polyp could be probable for single organ manifestation of IgG4-related disease (IgG4-RD), according to the comprehensive diagnostic criteria for IgG4-RD published in 2012; however, colonic manifestation of IgG4-RD has not been clarified owing to its rarity, and colon-specific criteria for IgG4-RD have not been proposed. Thus, we could not definitively establish the colonic polyp as IgG4-RD. Therefore, careful clinicopathological evaluation is needed to reveal whether this colonic polyp represents a nonspecific inflammatory response or an early manifestation of IgG4-RD.

Objective: Immunoglobulin (Ig)G4-related disease is a recently described systemic immune-mediated fibro-inflammatory disease that frequently occurs in tumorous form. Herein, we elucidated the clinicopathological and cytological characteristics of IgG4-related pleural lesions (PLs)., Patients and Methods: Among 22 patients with fibro-inflammatory PLs of idiopathic aetiology, eight cases were diagnosed as IgG4-PL and the remaining 14 as non-IgG4-PL according to comprehensive diagnostic criteria for IgG4-related disease. Cell block examination of pleural effusion (CBPE) was performed in five patients with IgG4-PL and in six with non-IgG4-PL. Both groups were compared in terms of clinical presentation, laboratory data, histopathological features of resected pleura, and cytological features of pleural effusion (PE)., Results: PE was the most common (six patients, 75%) clinical presentation of IgG4-PL. IgG4-PL comparatively showed significantly more frequent concomitant allergic disease (P = .021), higher serum IgE levels (P = .012), higher adenosine deaminase levels in pleural fluid (P = .005), and rare spontaneous recovery without treatment (P = .046). The IgG4-PL group was histologically characterised by thicker fibrous pleura, storiform fibrosis, and infiltration of regulatory T cells, eosinophils and basophils. Using CBPE, IgG4-PL was cytologically distinct with numerous IgG4+ cells and eosinophils. The cytology of CBPE positively correlated with the histology of pleural tissue in the number of IgG4+ cells and eosinophils (R = .769 and .803, respectively)., Conclusion: IgG4-PL frequently presents with PE and is histologically and cytologically characterised by abundant infiltration of IgG4+ cells and eosinophils. We believe that CBPE with immunohistochemistry/special staining could assist in the auxiliary diagnosis of IgG4-PL., (© 2018 John Wiley & Sons Ltd.)

Background: Immunoglobulin G4-related disease (IgG4-RD) encompasses a group of immune-mediated disorders that are gaining increasing recognition. Pulmonary presentations are common, with four types of patterns been described on radiography, including solid nodular, bronchovascular, ground glass opacities, and alveolar interstitial. Pleural thickening and pleural effusion have also been reported. However, there have been no reports of IgG4-RD that presents as spontaneous hemothorax., Case Presentation: A 61-year-old Chinese woman experienced recurrent right-sided chest pain and transient syncope. A significant decrease in her hemoglobin level and thick bloody pleural fluid demonstrated spontaneous hemothorax. The elevated serum IgG4 and histopathological analysis of the right pleura and intercostal lymph node specimens all supported the diagnosis of IgG4-RD in this patient. Further diagnostic evaluation did not reveal other causes for spontaneous hemothorax. She received steroids and no recurrent bleeding event occurred during a follow-up period of more than 1 year., Conclusion: Recurrent spontaneous hemothorax can be a rare manifestation of IgG4-RD, with pleural involvement as the most probable mechanism.

Objectives/hypothesis: The aim of this study was to evaluate the utility of 18 F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) for accurately diagnosing immunoglobulin G4-related sclerosing sialadenitis (IgG4-SS)., Study Design: Retrospective cohort study., Methods: We reviewed the records of 64 patients with IgG4-SS (35 male and 29 female patients) and 10 patients with clinically suspected IgG4-SS. Pathological diagnoses of patients clinically suspected with IgG4-SS included four cases of malignant lymphoma, one case of multicentric Castleman disease, one case of Sjögren's syndrome, and four cases of sialadenitis. All patients underwent submandibular gland (SMG) biopsies and baseline FDG-PET/CT evaluation. Clinical, serological, pathological, and PET/CT findings were analyzed. We also investigated maximum standardized uptake values (SUVmax) in the salivary glands of 15 patients with malignant disease of the salivary glands during the same period., Results: Increased FDG uptake in the SMG and parotid gland was found in 63 (98%) and 23 (35%) patients with IgG4-SS, respectively. FDG uptake of the bilateral SMG and unilateral SMG was recorded in 57 patients (89%) and six patients (9%), respectively. Mean SUVmax in patients with malignant disease of the salivary glands was significantly higher than that in patients with IgG4-SS (P = .035). We defined a positive test for IgG4-SS diagnosis as high SMG FDG uptake and serum IgG4 level ≥135 mg/dL, resulting in a sensitivity, specificity, and accuracy of 96.9%, 90.0%, and 86.4%, respectively., Conclusions: FDG-PET/CT findings in combination with serological and clinical findings may have the capacity to diagnose IgG4-SS and lead to less-invasive biopsy procedures., Level of Evidence: 4. Laryngoscope, 128:1120-1125, 2018., (© 2017 The American Laryngological, Rhinological and Otological Society, Inc.)

The salivary glands are commonly affected in systemic autoimmune disease and diseases of unknown pathogenesis. Sjögren syndrome (SjS) can be affected by other systemic diseases. Immunoglobulin G4-related disease (IgG4-RD) commonly affects salivary glands. Imaging findings are usually nonspecific; however, radiologists should be familiar with the manifestations to avoid diagnostic delay. Findings of early-stage SjS are difficult to identify on routine computed tomography or MR imaging. Chronic SjS can be diagnosed from MR imaging and sialographic findings. Multiglandular and localized involvement of IgG4-RD is difficult to differentiate from malignant lymphoma for multiglandular disease and salivary gland carcinoma for localized disease., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Immunoglobulin G4 (IgG4)-related disease (IgG4-RD) is an immune-mediated condition characterized by infiltration of the involved organs by IgG4-bearing plasma cells. The prevalence of autoimmune diseases, associated with or occurring in patients with human immunodeficiency virus (HIV) infection, has been increasing. We describe a 58-year-old man with an undiagnosed HIV infection, which presented as chronic cervical lymphadenopathy with an elevated serum IgG4 and a very high IgE. Histologically, lymph nodes showed expanded sinusoids and burnt-out germinal centers with increased plasmacytic infiltration and collagen fiber deposition. The absolute number of IgG4+ plasma cells and the IgG4+/IgG+ plasma cell ratio was increased. The lymph nodes were enlarged and clinically the patient improved after steroid treatment. Nine months later, he was diagnosed with acquired immune deficiency syndrome, following presentation with a cavitary left lung lesion. Immunohistochemical studies on the previously resected lymph node revealed complete absence of CD4+ T-lymphocytes and increased CD8+ T-lymphocytes. The pathologic findings met the criteria of both HIV infection and IgG4-related lymphadenopathy. Our case demonstrates that further investigations for underlying HIV infection in a case of IgG4-RD are critical, especially when extremely elevated IgE is concomitantly present.

Background: Immunoglobulin G4-related disease (IgG4-RD) is a rare multi-organ disorder. Physicians rarely encounter patients with IgG4-RD and its range of symptoms., Methods: To elucidate the clinical characterization of IgG4-RD, along with the clinical significance of lung involvement, we retrospectively reviewed the medical records of patients who satisfied the comprehensive diagnostic criteria for IgG4-RD., Results: We identified 52 patients with IgG4-RD. Of these, 32 patients underwent tissue biopsies, resulting in categorization as definite (n = 23) or possible (n = 9) IgG4-RD cases. Among the 23 definite IgG4-RD cases, those with positive lung involvement (n = 8) had significantly higher values of serum LDH (median 220 IU/L, interquartile range (IQR) 175-378 vs. median 184, IQR 136-249, p = 0.039), IgG (median 2769 mg/dL, IQR 2028-7807 vs. median 2048, IQR 1168-4376, p = 0.009), and soluble interleukin-2 receptors (median 1620 U/mL, IQR 871-2250 vs. median 733, IQR 271-1600, p = 0.003) than those with negative lung involvement (n = 15). Similarly, a significant number of patients with positive lung involvement were positive for rheumatoid factor (71.4% vs. 23.1%, p = 0.041) or hypocomplementemia (50% vs. 0%, p = 0.036). Sixteen patients also showed lung involvement (definite n = 8, possible n = 8); thoracic computed tomography (CT) of these patients revealed mediastinal lymphadenopathies (n = 14, 87.5%), ground glass opacity (n = 11, 68.8%), consolidation (n = 8, 50%), thickening of the bronchovascular bundles (n = 7, 43.8%), small nodules (n = 5, 31.3%), bronchiectasis (n = 4, 25%), and reticular shadows (n = 4, 25%), and pulmonary function tests, using a standard technique involving a single breath, revealed decreased diffusion capacity for carbon monoxide., Conclusions: IgG4-RD is associated with diverse thoracic CT findings and a decreased diffusion capacity, and careful multidisciplinary assessment is needed to enable differentiation of IgG4-RD from lymphoproliferative disorders., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Relapsing polychondritis (RP) is a rare systemic autoimmune disorder characterized by the episodic and progressive deterioration of cartilage inflammation. Approximately 30% patients with RP have concurrent disease. However, there have been no previous reports of RP complicated by immunoglobulin G4-related disease (IgG4-RD). Here we report the case of a 67-year-old male who developed IgG4-RD approximately 20 years after RP diagnosis. The association between IgG4-RD and RP remains unclear.

Immunoglobulin G4-related disease (IgG4-RD) is a systemic inflammatory condition characterized by tissue infiltration with IgG4 + plasma cells and an elevated serum IgG4 level. It usually occurs in middle-aged or older patients, with male predominance, and can involve multiple organs synchronously or metachronously. Patients with IgG4-RD generally respond to steroid therapy. IgG4-related skin lesions are typically erythematous and itchy plaques, subcutaneous nodules, or papules like prurigo nodularis located on the head and neck areas. Histologically, lymphoplasmacytic infiltrates with abundant IgG4+ plasma cells are seen in the dermis and/or subcutaneous tissue. The skin condition of IgG4-RD does not necessarily exhibit infiltration of IgG4 + plasma cells, which is a prerequisite for IgG4-related skin disease, but such skin lesions without infiltration by IgG4 + plasma cells can be included in the skin manifestations of IgG4-RD., (© 2017 Japanese Dermatological Association.)

A 50-year-old woman presented with epigastralgia. Computed tomography (CT) of the abdomen revealed a 6-cm well-enhanced mass extending from the left lobe of the liver to the abdominal wall, suggestive of cholangiocarcinoma. Liver and skin mass biopsies did not provide evidence of hepatic malignancy but were rich in plasma cells and sclerotic lesions. Subsequent detection of elevated serum immunoglobulin G4 (IgG4) led to a diagnosis IgG4-related inflammatory pseudotumor (IPT) of the liver. Treatment with systemic corticosteroids resulted in rapid clinical improvement. This case is the first report of an IgG4-related hepatic IPT invading the abdominal wall.

Aims: There have been few reports on immunoglobulin-G4 (IgG4)-related interstitial pneumonia (IP), and its clinical features remain unclear. The objective of this study was to assess whether IP with marked IgG4-positive plasma cell infiltration without extrathoracic lesions of IgG4-related disease (RD) should be diagnosed as a subtype of IgG4-RD or a separate entity., Methods and Results: All consecutive patients with surgical lung biopsy-proven idiopathic IP with an IgG4/IgG-positive cell ratio of >40% and >50 IgG4 + plasma cells in a high-power field without extrathoracic lesions of IgG4-RD were reviewed retrospectively. Five patients were enrolled into this study. All patients were male with a history of smoking. Four patients met the comprehensive diagnostic criteria for IgG4-RD. The remaining patient lacked data related to the serum IgG4 level. Histologically, a non-specific IP pattern was observed in all patients. The key morphological features of IgG4-RD, such as storiform fibrosis and obliterative phlebitis with lymphoplasmacytic infiltration in a loose background texture, were absent in every patient. In contrast, venule obstruction by densely packed lymphoplasmacytic infiltration was observed in two patients. Marked scarring and remodelling of the lung were also noted, which is not seen typically in IgG4-RD. A favourable response to corticosteroid monotherapy was observed in all patients; however, two patients developed lung cancer during the course of observation., Conclusions: IP with marked IgG4-positive plasma cell infiltration without extrathoracic lesions of IgG4-RD had different pathological features from those of IgG4-RD, and it is appropriate to regard this as a separate entity., (© 2016 John Wiley & Sons Ltd.)

A 76-year-old woman with multiple coronary risk factors was admitted to our hospital because of episodes of new-onset chest pain that had begun 3 days previously. She underwent percutaneous coronary intervention (PCI) for severe stenoses in the two high lateral (HL) branches. Intravascular ultrasound (IVUS) revealed massive stenotic lesions in the HL branches and tumorous nonstenotic lesions in the left anterior descending coronary artery (LAD) and the left circumflex coronary artery (LCx). iMAP™, optical coherence tomography (OCT), and coronary computed tomography angiography (CCTA) were performed. iMAP depicted fibrosis in the vessel (green areas) and nonfibrotic tissue change suggestive of inflammation outside the vessel (yellow/red areas). OCT revealed high-intensity homogenous intimal hyperplasia with superficial calcification, and CCTA showed massive periarterial soft lesions in the HL, LAD, and LCx. The serum IgG4 level was high at 252-427 mg/dL (8 measurements) (reference range, 4.8-105.0 mg/dL). We suspected IgG4-related coronary periarteritis on the basis of the comprehensive diagnostic criteria as a possible diagnosis. The clinical course was good after initial and subsequent PCIs for both the HL stenoses and the progressing LCx stenosis, and there was no recurrence of angina pectoris thereafter. Steroids were not administered because the massive lesions did not enlarge during the 16 months of follow-up. iMAP was able to evaluate the tissue characteristics of tumorous lesions in the stenosed HL branches and the nonstenotic LAD and LCx in a patient with an elevated level of IgG4.

We report a case of immunoglobulin G4-related disease (IgG4-RD) which presented with prurigo on the trunk and extremities. A 66-year-old man had a 2-month history of itchy erythematous papules on his trunk and extremities. Bilateral eyelid swelling and enlargement of the submandibular and parotid glands were also observed. Computed tomography revealed pleural thickening and diffuse pancreatic enlargement. Serum levels of IgG4 were markedly increased. A biopsy specimen obtained from an erythematous papule showed a perivascular inflammatory infiltrate of lymphocytes with eosinophils in the dermis, whereas a parotid gland biopsy revealed an infiltrate of abundant IgG4-positive plasma cells. Treatment with prednisolone resulted in improvement of the skin and other lesions along with a decrease in IgG4 serum levels. A flow cytometric assay revealed that percentages of interleukin (IL)-4- and IL-13-producing CD4(+) T cells were markedly higher in the circulation of the IgG4-RD patient than in that of healthy subjects. Moreover, those populations dramatically decreased after treatment. Thus, prurigo may be a skin manifestation of IgG4-RD and T-helper 2 cells may contribute to the pathogenesis., (© 2016 Japanese Dermatological Association.)

We report a case of immunoglobulin G4-related large thoraco-abdominal aortic aneurysm in a 38-year old man. Preoperative contrast-enhanced computed tomography revealed that the mid-descending thoracic aorta was extremely enlarged and the maximum diameter of the aneurysm was 92 mm. The patient underwent thoraco-abdominal aortic replacement through a thoraco-abdominal incision under left heart bypass. The postoperative pathological examination diagnosed immunoglobulin G4-related aortic aneurysm., (© The Author 2016. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.)

Background: Inflammatory pseudotumor is a rare clinical condition that can be related to immunoglobulin G4 disease. Only a few cases of spinal inflammatory pseudotumors have been reported in the literature and an association with immunoglobulin G4 disease was not conclusive in any of them. We describe what we believe to be the first biopsy-proven case of an epidural inflammatory pseudotumor related to immunoglobulin G4 disease., Case Presentation: A 57-year-old Caucasian woman presented to our hospital with severe paraparesis, gait disturbance, and sensory loss secondary to a relapsing epidural mass. Examination of a biopsy specimen revealed a lymphoplasmacytic infiltration with fibrosis and an immunoglobulin G4-positive plasma cell ratio of over 50 %, which are compatible with a diagnosis of immunoglobulin G4-related inflammatory pseudotumor. Our patient was successfully treated with systemic and epidural administration of glucocorticoids., Conclusion: Immunoglobulin G4-related disease is an emerging clinical condition in which central nervous system involvement is still uncommon. We describe the case of a patient with an epidural mass with medullar compression, which was proved to be an immunoglobulin G4-related epidural inflammatory pseudotumor. Our findings suggest a new manifestation of immunoglobulin G4-related disease. This disorder should be considered in the differential diagnosis of spinal tumors as a potentially treatable condition with glucocorticoids.

Objective: Because it is uncertain whether immunoglobulin G4-related disease (IgG4-RD) is associated with malignancy, we evaluated the incidence of cancer development in a large cohort of patients with IgG4-RD., Methods: The study enrolled 158 patients diagnosed as having IgG4-RD between 1992 and 2012. We calculated the standardized incidence ratio (SIR) and cumulative rate of malignancies in this group and searched for risk factors associated with the occurrence of tumors., Results: A total of 34 malignancies were observed in the patients with IgG4-RD over a mean followup period of 5.95 ± 4.48 years. The overall SIR of malignancies was 2.01 (95% CI 1.34-2.69). The SIR of patients who exhibited a tumor within 1 year after IgG4-RD diagnosis was 3.53 (95% CI 1.23-5.83), while that of subjects forming a malignancy in subsequent years was 1.48 (95% CI 0.99-1.98). The cumulative rate of malignancy development was significantly higher in patients with IgG4-RD within 12 years after diagnosis than in the Japanese general population. Comparable results were obtained for an autoimmune pancreatitis subgroup. The serum concentrations of several disease activity markers at diagnosis were significantly higher in patients with malignancies than in those without., Conclusion: We identified a close association between IgG4-RD and malignancy formation within 12 years after diagnosis, particularly during the first year. An active IgG4-RD state is presumed to be a strong risk factor for malignancy development.

Immunoglobulin G4 (IgG4)-related disease is a rare systemic diseases. A 67-year-old male presented at our institution with mild upper abdominal pain and jaundice for 20 d. Laboratory results revealed high levels of IgG4 (15.4 g/L, range: 0.08-1.4 g/L). Computed tomography (CT) showed significant enlargement of the entire pancreas and a capsule-like low-density rim surrounding the whole pancreas. Positron emission tomography/CT revealed increased uneven metabolism of the entire pancreas. Both magnetic resonance cholangiopancreatography and endoscopic retrograde cholangiopancreatography showed stenosis of the distal common bile duct and proximal main pancreatic duct, and dilation of the proximal common bile duct and extra- and intra-hepatic bile ducts. He was diagnosed with IgG4-related autoimmune pancreatitis. The patient was treated with prednisone for 14 mo. The patient responded well to prednisone but upon cessation of the corticosteroid developed enlargement of the submandibular gland. The patient's serum IgG4 was elevated at 23.9 g/L. It is important to maintain treatment, so the patient was again treated with prednisone and had a good response. Follow-up of IgG4-related disease is thus necessary.

Immunoglobulin G4-related disease is a fibroinflammatory condition of unclear etiology that can present with inflammatory changes and enlargement of a wide variety of organs, most commonly in the gastrointestinal tract. A diagnosis requires an elevated serum immunoglobulin G4 concentration and a tissue biopsy showing a dense plasma cell infiltrate with an increased percentage of immunoglobulin G4+ plasma cells. This disease infrequently presents in the genitourinary tract, and as such might be unfamiliar to and potentially overlooked by urologists. Here we present the third reported case of immunoglobulin G4-related disease manifesting as a mass in the urinary bladder., (© 2015 The Japanese Urological Association.)

Objectives: To evaluate the usefulness of sonography for monitoring the response to glucocorticoid treatment in patients with immunoglobulin G4 (IgG4)-related disease., Methods: We conducted a retrospective study using sonography in 12 patients with bilateral swollen submandibular glands who had a diagnosis of IgG4-related disease based on an elevated serum IgG4 level (>135 mg/dL) and histopathologic findings between January 2010 and December 2012. Among these patients, 6 were treated with prednisolone, and the other 6 were placed under observation. B-mode sonographic examinations of the submandibular glands were performed with or without color Doppler imaging at the initial examination and 6 months later. Findings were compared between the groups (treated and untreated), and their relationship with the treatment response of the primarily involved organs was investigated., Results: In the treated group, the submandibular glands of all 6 patients decreased in both size and volume after treatment (average volume ± SD, 27,449.7 ± 24,227.6 to 4609.7 ± 1911.4 mm(3); P = .004). The internal echo texture, characterized by multiple hypoechoic foci scattered against a heterogeneous hyperechoic background of submandibular tissue with demarcated hyperechoic lines, with or without hypoechoic tumor formation, disappeared or was obscured in all cases. In addition, the blood flow signals were reduced in all 3 patients who underwent color Doppler sonography, and the response observed on sonography was found to correlate with the IgG4 level and recovery of specific organ involvement. In contrast, in the untreated group, the submandibular glands showed a tendency to increase in both size and volume (average volume, 9326.3 ± 3054.8 to 12,217.4 ± 4605.5 mm(3); P= .2) without a decrease in the blood flow signals., Conclusions: Sonography is considered useful for evaluating the response to glucocorticoid therapy in patients with IgG4-related disease of the submandibular glands., (© 2015 by the American Institute of Ultrasound in Medicine.)

Immunoglobulin G4-related disease is a recently described systemic clinicopathological entity characterized by immunoglobulin G4-producing plasmacytic infiltration of tissue and frequently by elevated serum immunoglobulin G4 concentration. Manifestations of this disease have been documented in nearly all organs and locations, but coronary artery involvement is not widely recognized. We report the coronary findings of a patient with multi-organ immunoglobulin G4-related disease. Non-electrocardiogram-gated computed tomography of the chest demonstrated nodular and rind-like periarterial soft tissue thickening along the proximal coronary artery segments with improvement following steroid therapy.

Retroperitoneal fibrosis is a rare disease characterized by the development of inflammation and fibrosis in the soft tissues of the retroperitoneum and other abdominal organs. Retroperitoneal fibrosis can be of 2 types: idiopathic and secondary. The recently advocated concept and diagnostic criteria of immunoglobulin G4 (IgG4)-related disease, derived from research on autoimmune pancreatitis (AIP), has led to widespread recognition of retroperitoneal fibrosis as a condition caused by IgG4-related disease. We now know that previously diagnosed idiopathic retroperitoneal fibrosis includes IgG4-related disease; however, the actual prevalence is unclear. Conversely, some reports on AIP suggest that retroperitoneal fibrosis is concurrently found in about 10% of IgG4-related disease. Because retroperitoneal fibrosis has no specific symptoms, diagnosis is primarily based on diagnostic imaging (computed tomography and magnetic resonance imaging), which is also useful in evaluating the effect of therapy. Idiopathic retroperitoneal fibrosis can occur at different times with other lesions of IgG4-related disease including AIP. Thus, the IgG4 assay is recommended to diagnose idiopathic retroperitoneal fibrosis. High serum IgG4 levels should be treated and monitored as a symptom of IgG4-related disease. The first line of treatment for retroperitoneal fibrosis is steroid therapy regardless of its cause. For patients with concurrent AIP, i.e., IgG4-related retroperitoneal fibrosis, the starting dose of steroid is usually 30-40 mg/d. The response to steroid therapy is generally favorable. In most cases, the pancreatic lesion and retroperitoneal fibrosis improve after the initial treatment. However, the epidemiology, treatment for recurring retroperitoneal fibrosis, and long-term prognosis are still largely unknown. Further analysis of such cases and research are necessary.

Most primary aortoduodenal fistulas occur in the presence of an aortic aneurysm, which can be part of immunoglobulin G4 (IgG4)-related sclerosing disease. We present a case who underwent endovascular grafting of an aortoduodenal fistula associated with a high serum IgG4 level. A 56-year-old male underwent urgent endovascular reconstruction of an aortoduodenal fistula. The patient received antibiotics and other supportive therapy, and the postoperative course was uneventful, however, elevated levels of serum IgG, IgG4 and C-reactive protein were noted, which normalized after the introduction of steroid therapy. Control computed tomography angiography showed no endoleaks. The primary aortoduodenal fistula may have been associated with IgG4-related sclerosing disease as a possible complication of IgG4-related inflammatory aortic aneurysm. Endovascular grafting of a primary aortoduodenal fistula is an effective and minimally invasive alternative to standard surgical repair.

Immunoglobulin G4 (IgG4)-related disease is an immune-mediated disorder that commonly manifests in the salivary glands. As a recently described disorder, the description and classification of IgG4-related disease is an ongoing process. Diagnosis of IgG4-related disease requires integration of clinical history, histopathology, and radiographic findings, including ultrasonography and sialography. In this case report, we correlate parotid ultrasonographic and sialographic findings in a patient with proven IgG4-related disorder confirmed from analysis of previous submandibular gland resections. We aim to highlight the utility of multimodality imaging in the diagnosis of IgG4-related disease. [ABSTRACT FROM AUTHOR]

Abstract Objective The authors investigated the expression of IgG4 and IgG in cutaneous Rosai-Dorfman Disease (CRDD) to further improve the understanding of this disease. Methods The authors retrospectively reviewed the clinicopathological features of 23 CRDD patients. The authors diagnosed CRDD by the presence of emperipolesis and immunohistochemical (IHC) staining of histiocytes consisting of S-100(+)/CD68(+)/CD1a(-) cells. The expressions of IgG and IgG4 in cutaneous specimens were assessed by IHC (EnVision) and quantitatively calculated by a medical image analysis system. Results All 23 patients, including 14 males and 9 females, were confirmed to have CRDD. Their ages ranged from 17 to 68 years (mean 47.91 ± 14.16). The most frequently affected skin regions were the face, followed by the trunk, ears, neck, limbs, and genitals. In 16 of these cases, the disease presented as a single lesion. IHC staining of sections showed that IgG was positive (≥ 10 cells/High-Power Field [HPF]) in 22 cases, while IgG4 was positive (≥ 10 cells/HPF) in 18 cases. Moreover, the IgG4/IgG proportion ranged from 1.7% to 85.7% (mean 29.50 ± 24.67%, median 18.4%) in the 18 cases. Study limitations In the majority of studies, as well as in the current study, the design. RDD is a rare disease, so the sample size is small. In the next studies to come, the authors will expand the sample for multi-center verification and in-depth study. Conclusion The positive rates of IgG4 and IgG and the IgG4/IgG ratio assessed through IHC staining may be important in understanding the pathogenesis of CRDD.

Immunoglobulin G4-related disease (IgG4-RD) is an immune-mediated fibroinflammatory disease. IgG4-RD can affect any organ system, including the pancreas, bile ducts, salivary glands, mesentery, and retroperitoneum. On the other hand, small intestine involvement is extremely rare. This paper describes a case of IgG4-RD involving the small bowel, particularly at the distal ileum. An 81-year-old female was admitted to the authors’ hospital complaining of abdominal pain, dyspepsia, and hematochezia. The laboratory tests, including tumor markers and IgG4, were within normal limits. A colonoscopy did not show any abnormal findings. Abdominal computed tomography revealed segmental aneurysmal dilatation and wall thickening at the distal ileum, suggesting malignant conditions, such as small bowel lymphoma. The patient underwent an exploratory laparoscopy and ileocecectomy to differentiate a malignancy. A histopathology examination revealed dense lymphoplasmacytic infiltration, storiform fibrosis, and IgG4-positive plasma cells (>50 per high power field). The patient was finally diagnosed with IgG4-RD. The patient was followed up in the outpatient clinic for five years without recurrence. This paper suggests that a radical resection without maintenance therapy can be a treatment option, particularly when the IgG4-RD manifests as a localized gastrointestinal tract lesion.

IgG4-related disease (IgG4-RD) is a systemic inflammatory disease characterized by IgG4-positive plasma cell and T lymphocyte infiltration of multiple organs. It commonly involves the pancreas, lacrimal glands, and salivary glands, and it has been rarely reported in the sinonasal cavity. We herein report the case of a 47-year-old male patient whose chief complaint was decreased visual acuity. A tumefactive mass was found on imaging studies, originating from the sinonasal cavity and invading the orbit, kidney, and meninges. The mass was resected through endoscopic sinus surgery and was pathologically confirmed to be IgG4-RD. The patient was treated with steroid therapy and showed clinical improvement.

Despite causing high morbidity, IgG4-related disease (IgG4-RD) and its gastroenterological manifestations lack better and greater theoretical contributions. Therefore, the objective of this work was to evaluate the clinical–epidemiological, diagnostic and treatment aspects of the gastrointestinal manifestations of this disease. A systematic review was carried out using the PubMed, Scopus and Embase databases between January 2012 and March 2023 with the following descriptors: "Immunoglobulin G4-Related Disease" (MeSH) AND #2 "Gastrointestinal Tract" (MeSH). Our data collection grouped a total of 3607 patients from mostly epidemiological cohort studies and cross-sectional follow-ups. In the subgroup analysis, IgG4-RD was associated with male gender, with an estimated prevalence between 54% and 80%. In our findings, the prevalence by topography was presented in the following ranges: lacrimal glands (17–57%); salivary glands (28–72%); pancreas (19–60%); biliary tract (5–40%); retroperitoneal cavity (9–43%). Longitudinal studies are needed to better map the natural history of the gastrointestinal manifestations of IgG4-RD and enable the formulation of individualized treatments. [ABSTRACT FROM AUTHOR]

Background and Aims: Immunoglobulin G4‐related sclerosing cholangitis (IgG4‐SC) is considered a biliary manifestation of IgG4‐related diseases. However, there has been a controversy on the clinical outcomes according to the location of the involved bile duct. We therefore compared the clinical outcomes and long‐term prognosis of IgG4‐SC with proximal bile duct involvement (proximal IgG4‐SC) and IgG4‐SC with distal bile duct involvement (distal IgG4‐SC). Methods: We reviewed the data of patients with IgG4‐SC that were prospectively collected at 10 tertiary centers between March 2002 and October 2020. Clinical manifestations, outcomes, association with autoimmune pancreatitis (AIP), steroid‐responsiveness, and relapse of IgG4‐SC were evaluated. Results: A total of 148 patients (proximal IgG4‐SC, n = 59; distal IgG4‐SC, n = 89) were analyzed. The median age was 65 years (IQR, 56.25–71), and 86% were male. The two groups were similar in terms of jaundice at initial presentation (51% vs 65%; P = 0.082) and presence of elevated serum IgG4 (66% vs 70%; P = 0.649). The two groups showed significant differences in terms of steroid‐responsiveness (91% vs 100%; P = 0.008), association with AIP (75% vs 99%; P = 0.001), and occurrence of liver cirrhosis (9% vs 1%; P = 0.034). During a median follow‐up of 64 months (IQR, 21.9–84.7), the cumulative relapse‐free survival was significantly different between the two groups (67% vs 79% at 5 years; P = 0.035). Conclusions: Relapse of IgG4‐SC frequently occurred during follow‐up. Proximal IgG4‐SC and distal IgG4‐SC had different long‐term outcomes in terms of steroid‐responsiveness, occurrence of liver cirrhosis, and recurrence. It may be advantageous to determine the therapeutic and follow‐up strategies according to the location of bile duct involvement. [ABSTRACT FROM AUTHOR]

Immunoglobulin G4-related disease (IgG4-RD) is a rare fibro-inflammatory condition characterized by IgG4-expressing plasma cell infiltration of the skin and other organs, leading to profound itchiness. Oral corticosteroids are the first-line therapy for IgG4-RD but relapses and potential side effects are common. In this case, we discuss a patient with a hyperpigmented, scaling dermatitis on his arms, back, and chest with lichen amyloidosis (LA) that incompletely responded to corticosteroids. He had reduced quality of life secondary to chronic pruritus. Dupilumab, an IL-4 and IL-13 inhibitor, was initiated. He experienced a transient worsening, followed by complete resolution of his itch with remission of his rash. While the pathogenesis of IgG4-RD is not entirely understood, a T-helper 2 (Th2) immune response has been implicated, with interleukins (IL) 4, 5, 10, and 13 playing a role in IgG4 class switch, resulting in eosinophilia and elevated IgE. The strong response of dupilumab in this case may provide evidence in favor of the involvement of IL-4 and IL-13 in the pathogenesis of cutaneous IgG4-RD. Future clinical studies involving larger patient populations may be warranted. [ABSTRACT FROM AUTHOR]

BackgroundFamily screening of a 48-year-old male with recently diagnosed IgG4-related disease (IgG4-RD) revealed unanticipated elevations in plasma IgG4 in his two healthy teenaged sons.MethodsWe performed gene sequencing, immune cell studies, HLA typing, and analyses of circulating cytotoxic CD4+ T lymphocytes and plasmablasts to seek clues to pathogenesis. DNA from a separate cohort of 99 patients with known IgG4-RD was also sequenced for the presence of genetic variants in a specific gene, FGFBP2.ResultsThe three share a previously unreported heterozygous single base deletion in fibroblast growth factor binding protein type 2 (FGFBP2), which causes a frameshift in the coding sequence. The FGFBP2 protein is secreted by cytotoxic T-lymphocytes and binds fibroblast growth factor. The variant sequence in the FGFBP2 protein is predicted to form a disordered random coil rather than a helical-turn-helix structure, unable to adopt a stable conformation. The proband and the two sons had 5-10-fold higher numbers of circulating cytotoxic CD4 + T cells and plasmablasts compared to matched controls. The three members also share a homozygous missense common variant in FGFBP2 found in heterozygous form in ~40% of the population. This common variant was found in 73% of an independent, well characterized IgG4-RD cohort, showing enrichment in idiopathic IgG4-RD.ConclusionsThe presence of a shared deleterious variant and homozygous common variant in FGFBP2 in the proband and sons strongly implicates this cytotoxic T cell product in the pathophysiology of IgG4-RD. The high prevalence of a common FGFBP2 variant in sporadic IgG4-RD supports the likelihood of participation in disease.

Immunoglobulin G4-related ophthalmic disease (IgG4-ROD) is a cause for orbital and ocular inflammation. Involvement of the sclera and intraocular tissues is less common, and presentation is mostly unilateral. We hereby describe a probable case of steroid-resistant intraocular IgG4-ROD presenting as a choroidal mass in the left eye, with sequential anterior uveitis and scleritis of the fellow right eye. The diagnostic path was not straightforward and included subconjunctival biopsy, blood tests, magnetic resonance imaging, positron emission tomography-computed tomography, and biopsies in two extra-ocular sites. Disease progression was rapid in the left eye despite high-dose oral steroids, while the inflammation of the fellow eye was controlled with the use of rituximab and secondline immunosuppressants. At the 3-year follow-up, the ocular inflammation was well controlled. The left eye was phthisical, but the right eye maintained a visual acuity of 20/20. [ABSTRACT FROM AUTHOR]

Subepithelial tumors (SETs) are often found accidentally during gastroscopy, most commonly in the stomach. If a raised lesion is observed around the major papilla, the relationship with the common bile duct or pancreas should be evaluated, and not only SET but also cancer or autoimmune disease should be considered in the differential diagnosis. Herein, we present a case of prominent major papilla mimicking a SET that was accidentally discovered during endoscopy. The patient was asymptomatic, and the physical and laboratory findings were normal. The biopsy findings were nonspecific and imaging findings suggested possible malignancy; thus, surgical ampullectomy was performed. The histopathological results confirmed IgG4-related ampullitis. This case suggests that immunoglobulin G4 (IgG4)-related disease may manifest with atypical findings, hindering its diagnosis and treatment. [ABSTRACT FROM AUTHOR]

Immunoglobulin G4 (IgG4)-related disease is a rare systemic fibroinflammatory condition characterized by elevated serum IgG4 levels and infiltration of IgG4-positive plasma cells in various organs. IgG4-related lung disease shows varied radiologic features on chest CT. Patients usually present with a solid nodule or mass mimicking lung cancer; therefore, distinguishing between IgG4-related disease and other conditions is often challenging. Additionally, co-existing radiologic findings of IgG4- related lung disease may mimic metastasis or lymphangitic carcinomatosis of the lung. We report two cases of histopathologically confirmed IgG4-related lung disease mimicking lung cancer. Chest CT revealed a solid nodule or mass with ancillary radiologic findings, which suggested lung cancer; therefore, IgG4-related lung disease was radiologically indistinguishable from lung cancer in both cases. Measurement of serum IgG4 levels and clinical evaluation to confirm involvement of various organs may be useful to establish the differential diagnosis. However, surgical biopsy evaluation is needed for confirmation. [ABSTRACT FROM AUTHOR]

Abstract Introduction Immunoglobulin G subclass measurements are important for the diagnostic work‐up of immunodeficiencies and immunoglobulin G4 (IgG4) related diseases. It is currently unknown whether a single sampling is truly representative for an individual's IgG subclass concentrations. This study aimed to investigate whether IgG and IgG subclass concentrations in healthy individuals are stable over time. Method With a span of median 42 weeks, four samples from each of 54 (34M, 20F) healthy adult volunteers (24–66 years) were analyzed for IgG and IgG1–4 using turbidimetry. Concentrations were compared within and between individuals. Results IgG and IgG subclass concentrations followed either a normal (IgG, IgG1, and IgG3) or log normal (IgG2 and IgG4) distribution. Immunoglobulin 4 demonstrated by far the widest range of concentrations between individuals (670‐fold: 0.004–2.68 g/L). Immunoglobulin G subclass variations within individuals were expressed as pooled standard deviations (PSD). These ranged from 0.056 (IgG4) to 0.955 g/L (IgG) and correlated with mean concentration of IgG or the particular IgG subclass. As a consequence, the relative PSDs (i.e., PSD divided by mean IgG or IgG subclass concentration) fell within a narrow range: 5.82%–10.1%. Based on these numbers, the 95%‐upper one‐sided confidence limits for intraindividual IgG and IgG subclass variation was calculated to range from 9.82% (IgG2) to 16.9% (IgG4). Conclusion The study documents that IgG or IgG subclass concentrations within healthy individuals are very stable over at least 42 weeks. The expected variation for IgG4 concentrations at a 95% confidence level does not exceed ±16.9%.