International Consensus Guidance Statement on the Management and Treatment of IgG4-Related Disease

Steroid-induced reconstitution of the biliary tree ravaged by IgG4-related disease

The steroid-induced, rapid healing of the biliary tree ravaged by IgG4-related disease shows that the point of irreversibility remains to be defined.

[IgG4-Related Orbitopathy as an Important Differential Diagnosis of Advanced Silent Sinus Syndrome. German version]

Hintergrund

Mit Immunglobulin (Ig)G4 assoziierte Erkrankungen werden als immunvermittelte Erkrankungen klassifiziert. Die Ätiologie dieser Krankheiten ist bisher noch nicht geklärt. Sie manifestieren sich auf verschiedene Weise, und die gleichzeitige Beteiligung mehrerer Organe ist nicht ungewöhnlich.

Kasuistik

Es wird der Fall eines Patienten vorgestellt, der in die Klinik der Autoren überwiesen wurde, nachdem mehrere erfolglose Nasennebenhöhlenoperationen bei ihm durchgeführt worden waren; bei Vorliegen eines Enophthalmus und einer resultierenden Durchwanderungskeratitis bestand die Verdachtsdiagnose eines Silent-Sinus-Syndroms. Der Erhalt der Orbita war nicht mehr möglich. Nach 5 Jahren ohne definitive Diagnose wurde nun die Diagnose einer IgG4-assoziierten Erkrankung gesichert.

Diskussion

IgG4-assoziierte Erkrankungen stellen einen wichtigen Baustein bei der Differenzialdiagnose chronischer fortgeschrittener Erkrankungen der Orbita und der Nasennebenhöhlen dar. Bei unklaren Krankheitszeichen sollte diese Diagnose in Erwägung gezogen werden. Zu den typischen histologischen Befunden gehören ein storiformes Muster der Fibrose, Vaskulopathie und Gewebeinfiltration durch IgG4-Plasmazellen.

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.

IgG4-related disease: a contemporary review

Background/aim

Immunoglobulin G4-related disease (IgG4-RD), is an immune-mediated fibroinflammatory condition, which may involve multiple organs and mostly presents with high serum IgG4 levels and specific histopathological characteristics. As IgG4-RD is a relatively new entity the etiology, prevalence and epidemiologic knowledge is quite limited. Although involvement of almost all anatomical regions has been reported, the most commonly affected regions are pancreas, lacrimal glands, salivary glands, retroperitoneum, orbita, lymph nodes, kidney and lungs. Diagnosis is made with combined evaluation of clinical, radiological and histopathological findings. Typical histopathological features include storiform fibrosis, dense lymphoplasmacytic infiltrates and obliterative phlebitis. Its course is typically marked by remission and relapsing attacks and it may lead to fibrosis, destructive lesions in tissues and organ failure unless promptly treated. In the treatment of IgG4-RD, many approaches including surgical resection of tissues, systemic glucocorticoids, steroid-sparing immunosuppressive drugs, and biological agents are employed. Although association is not clear, malignancies are frequently reported in IgG4-RD patients. Therefore, it is prudent to monitor patients for the symptoms of malignant diseases.

Conclusion

In this review, recent advances in clinico-pathological characteristics, diagnosis, and treatment of IgG4–RD are discussed.

IgG4-related disease with multiple organs involvement was effectively controlled by glucocorticoids: a case report

Immunoglobulin G4 (IgG4) related disease is a rare autoimmune disease involving multiple organs and tissues. A diagnosis of IgG4-related disease (IgG4-RD) is mainly based on serum IgG4 concentration, imaging, pathology, and effective glucocorticoids therapy. In this paper, we report a 53-year-old male with typical signs and symptoms of IgG4-RD successfully treated with glucocorticoids. This patient had experienced bilateral mumps for more than 8 months and intermittent abdominal pain spreading to his lower back for 2 months before his admission. During his hospitalization, based on the characteristic appearance of magnetic resonance imaging (MRI), magnetic resonance cholangiopancreatography (MRCP), and computed tomography with positron emission tomography, a diagnosis of autoimmune pancreatitis (AIP), cholangitis with biliary obstruction, lachrymal adenitis, and submandibular adenitis was made. A high serum IgG4 concentration further supported a diagnosis of IgG4-RD. Then, the treatment was promptly initiated with corticosteroids. MRI, MRCP, and IgG4 concentration were re-examined during his follow up, suggesting that glucocorticoid treatment resulted in a resolution of his disease. The dosage of glucocorticoid had been gradually decreased. Now, he is stable with oral low-dose glucocorticoids. Certainly, long-term follow up of this patient with such a rare disease is very essential to observe the possibility of disease recurrence and glucocorticoids related complications.

Primary Immunoglobulin G4-Related Laryngeal Disease: A Case Series and Review of Literature

Objective:

Immunoglobulin G4-related disease (IgG4-RD) is an increasingly recognised cause of various systemic fibro-inflammatory conditions. However, laryngeal involvement as a primary feature is extremely rare. We aimed to report on a case series of such patients and examine the global literature relating to laryngeal involvement.

Methods:

Having previously reported a case of IgG4-RD laryngeal pseudotumour, we describe a case series of further 4 patients with primary laryngeal IgG4-RD managed by our UK quaternary airway service and provide a brief overview of laryngeal IgG4-RD.

Results:

Including our cases, 14 cases of primary laryngeal IgG4-RD have been reported. Vocal cord involvement is relatively uncommon. Repeat biopsies may be required to achieve histological diagnosis. Remission is achievable by commencement of immunomodulatory treatment, following which laryngeal reconstruction may be necessary.

Conclusion:

Laryngeal involvement is a rare presentation of IgG4-RD, itself a rare and difficult-to-diagnose condition. A high and prolonged index of suspicion is necessary from both surgical and pathological specialists for correct diagnosis and management.

Long-term clinical course and outcomes of immunoglobulin G4-related lung disease

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.

Idiopathic membranous nephropathy in a patient diagnosed with IgG4-related disease: A case report

RATIONALE

Immunoglobulin (Ig) G4-related disease (IgG4-RD) is a newly recognized, systemic disease. Membranous nephropathy is the most common glomerular lesion in IgG4- related kidney disease. However, the lack of relationship with IgG4-related kidney disease and monoclonal gammopathy of undetermined significance (MGUS) warrants investigation of the potential mechanisms.

PATIENT CONCERNS

A 62-year-old patient was diagnosed with IgG4-RD, tubulointerstitial nephritis, retroperitoneal fibrosis. After 2 years, she was presented with proteinuria, hypoproteinemia, facial, and bilateral lower limb edema. Furthermore, this patient exhibited deposits of IgG k of monoclonal hyperplasia, and bone marrow plasma cell count was 2.5%.

DIAGNOSIS

The patient was diagnosed with nephrotic syndrome, acute kidney injury, and MGUS. The pathological diagnosis was IgG4-related tubulointerstitial nephritis, IgG4-related membranous nephropathy.

INTERVENTIONS

The patient was treated with intravenous methylprednisolone (40 mg daily), which was changed to oral prednisone 50 mg/d after 2 months.

OUTCOMES

After 1 month, the patient exhibited a rapid response only with corticosteroid, and experienced partial remission of serum albumin and proteinuria.

LESSONS

This case may suggest a possible relationship between IgG4-RD and MGUS, provide some guidance for investigating the mechanism between them.

Immunoglobulin G4-related hypertrophic pachymeningitis with spinal cord compression: A case report

IgG4-related disease (IgG4-RD) is a recently recognized inflammatory condition that can be found in many organs. However, spinal involvement is rare and has been described only in case reports and series. Here, we report a rare case of spinal IgG4-RD that resulted in hypertrophic pachymeningitis with spinal cord compression. This case expands the phenotypic presentation for the neurological sequelae of IgG4-RD. Our case hints that spinal IgG4-RD may be misdiagnosed, and IgG4-RD in patients should be considered when the patient has a dural mass. Although early surgery, steroids, and/or immunosuppressive therapy may prevent neurological complications, the side effects should receive more attention during treatment.

A uterine pseudotumor of immunoglobulin G4-related disease

Immunoglobulin G4-related disease (IgG4-RD) is characterized by systemic lesions presenting as swellings, nodules and wall thickenings. The first-line therapy is glucocorticoids. This disease is common among middle-aged and elderly men, and its uterine mass formation is uncommon. We encountered a 39-year-old nulliparous woman with an IgG4-related uterine mass and enlarged pelvic lymph nodes. Complete remission was achieved by fertility-sparing resection of the uterine mass without glucocorticoids. This case showed that IgG4-RD can present as a uterine mass and we need to be careful of its diagnostic and therapeutic strategies because an IgG4-related uterine mass is difficult to distinguish from sarcoma or malignant lymphoma. Our case also demonstrated that IgG4-related lymphadenopathy could regress spontaneously without complete lymphadenectomy or glucocorticoids when IgG4-RD does not affect vital organs. A pelvic mass with hyperproteinemia may be a hint to remind us of IgG4-RD and may trigger a preoperative immunoglobulin test.

Rosai-Dorfman disease mimicking IgG4-related diseases: a single-center experience in China

Background

Rosai–Dorfman disease (RDD) and IgG4-related (IgG4-RD) disease are both rare diseases, but in some cases, RDD mimics IgG4-RD clinically and pathologically. RDD mimicking IgG4-RDs (RDD mimic IgG4-RD), referring to disease initially diagnosed as IgG4-RD but finally pathologically confirmed to be RDD, is a clinically rare and confusing disease. To summarize the characteristics of this disease, we prospectively analyzed the clinical features, laboratory parameters, pathological characteristics, treatment and prognosis of patients diagnosed with RDD mimic IgG4-RD. Moreover, by analyzing characteristics of RDD mimic IgG4-RD, RDD and IgG4-RD, we further compared the similarities and differences between RDD and IgG4-RD.

Results

7 patients with RDD mimic IgG4-RD were included in this study and all of them had extranodal organ involvement, especially the central nervous system, which occurred in 5 patients (71.4%). Although serum IgG4 level was elevated in 6 cases (1360–54,100 mg/L), overall, it was still lower than that in IgG4-RD patients. Furthermore, we found a new cut-off value of serum IgG4 concentration for differentiating RDD and IgG4-RD with higher specificity. Pathological findings of RDD also showed features resembling IgG4-RD: IgG4-positive plasma cell enrichments were observed in all RDD mimic IgG4-RD patients, and the proportion of IgG4/IgG in tissues was 10–40% in 4 patients and more than 40% in 2 patients. However, none of the RDD mimic IgG4-RD patients or RDD patients displayed obliterative phlebitis or storiform fibrosis. Most of the RDD mimic IgG4-RD patients were treated with glucocorticoids combined with immunosuppressants, and a good prognosis was obtained following treatment.

Conclusions

RDD has clinical manifestations that mimic IgG4-RD. However, detailed differences in laboratory parameters and pathological characteristics are present between these two diseases. Our study underlines the necessity to rule out RDD while diagnosing IgG4-RD using pathological findings as the identification criteria and provides advice for both differentiating these two diseases and clinical treatment of RDD mimic IgG4-RD.

A rare case report of immunoglobulin G4-related sclerosing mesenteritis and review of the literature

INTRODUCTION

Immunoglobulin G4 (IgG4)-related disease (IgG4-RD) is a rare autoimmune disorder involving 1 or multiple organs, most commonly the pancreas, lacrimal glands, and salivary glands. However, IgG4-related sclerosing mesenteritis (SM) involving the small-bowel mesentery is rare. Given that IgG4-related SM usually mimics the imaging characteristics of mesenteric malignancies, its preoperative diagnosis remains challenging. In addition, no specific consensus has been reached regarding the treatment of IgG4-related SM. Therefore, a better understanding of the characteristics, treatment, and prognosis of IgG-related SM is urgently needed. Herein, we report a rare case of IgG-related SM.

PATIENT CONCERNS

A 67-year-old man was admitted to our hospital after incidental detection of an abdominal mass on ultrasound imaging, although he reported being generally well. The findings on triple-phase abdominal computed tomography were highly consistent with a malignant mesenteric tumor.

DIAGNOSES

The hallmark histopathological features along with elevated levels of IgG4 (145 mg/dL) and imaging findings were indicative of IgG-related SM.

INTERVENTIONS

The patient was treated surgically. Postoperative histopathological examinations exhibited tissue infiltration with lymphocytes and IgG4-positive plasma cells, as well as fibrosis.

OUTCOMES

Ten days after surgery, the patient was discharged from the hospital, and did not show any clinical sign of IgG-related SM within 1-year follow-up.

CONCLUSION

This case highlights the mesentery as an uncommon site of involvement as well as how early IgG-related SM can be completely asymptomatic. Thus, this study has advanced our knowledge of IgG-related SM and may improve treatments for similar conditions.

Immunoglobulin G4-related sclerosing cholangitis mimicking cholangiocarcinoma: a case report and literature review

Immunoglobulin G4 (IgG4)-related disease (IgG4-RD) is a novel clinical disease that is characterized by elevated serum IgG4 concentrations and tumefaction or tissue infiltrated by IgG4+ plasma cells. The clinical manifestations of IgG4-RD depend on the type of tissues affected. IgG4-related sclerosing cholangitis is a type of IgG4-RD. We report a patient who initially visited a local hospital with a 5-month history of jaundice. He was found to have a mass in the upper part of the common bile duct that mimicked cholangiocarcinoma. He underwent surgery in our hospital and was later diagnosed with IgG4-related sclerosing cholangitis. We administered prednisolone 40 mg once a day for treatment. Taking into account the possible side effects of moderate-dose hormone therapy, we also administered teprenone, potassium chloride, and calcium carbonate. The patient did not have any recurrence of symptoms or adverse drug reactions during follow-up.

IgG4 thyroiditis in the Asian population

Immunoglobulin G4-related disease (IgG4-RD) is an immune-mediated fibro-inflammatory condition that often causes the formation of tumefactive lesions. The discovery of IgG4-RD linked many well-known isolated conditions as a distinct multi-organ disease, and started an era of promoting investigation and treatment in relevant fields. In the thyroid gland, a subcategory of Hashimoto thyroiditis (HT) with IgG4-rich inflammation was first discovered and named IgG4 thyroiditis by our group. This subtype of HT presents with rapidly progressive clinical manifestations and destructive histopathological features underlying thyroid dysfunction, which are significantly different from the common type of HT. Moreover, other IgG4-rich thyroid conditions in patients with Graves' disease and systemic IgG4-RD have been described. These observations are most frequently reported in the Asian population for unknown reasons. Although recent studies demonstrated that IgG4 thyroiditis is a specific entity independent from IgG4-RD, recognition of this unique subset of thyroid disease has yielded important insights into understanding its pathogenesis and the development of novel therapeutic approaches.

IgG4-related disease: an update on pathophysiology and implications for clinical care

IgG4-related disease (IgG4-RD) has only existed as a unique disease entity since 2003, yet remarkable progress has already been achieved in describing the essential features of the disease. A framework for systematic clinical studies has been created by the development of a quantitative disease activity tool (the IgG4-RD Responder Index) and the validation of classification criteria, both of which were the products of international, multi-centre investigations. In addition, substantial strides have been made in understanding the pathophysiology of IgG4-RD. In particular, the central role of B cells in the disease has been demonstrated by both the robust clinical responsiveness of IgG4-RD to B cell depletion and by the identification of multiple self-antigens that promote B cell expansion. CD4⁺ T cells have also been investigated in detail; CD4⁺ cytotoxic T lymphocytes (suspected of promoting disease) and a specific T follicular helper cell subset that contributes to IgG4 isotype switching have both been defined by multiple groups. The mechanisms by which these immune cells converge on target tissues, interact with fibroblasts and promote tissue remodelling are beginning to be understood and will be an important research focus in the coming years.

Prediction of 3-month treatment outcome of IgG4-DS based on BP artificial neural network

OBJECTIVE

The study aimed to establish an effective back-Propagation artificial neural network (BP-ANN) model for automatic prediction of 3-month treatment outcome of IgG4-DS.

METHODS

A total of 26 IgG4-DS patients at Shanghai Ninth People's Hospital from January 2018 to December 2019 were involved in the study. They were all followed for >3 months. The primary outcome was reduction of serum IgG4 (sIgG4) after 3-month treatment. The association between risk factors and reduction of sIgG4 was analyzed by Spearman's rank correlation test. According to the R values, we built a BP-ANN model by MATLAB R2019b.

RESULTS

The average reduction of sIgG4 was 5.55 ± 5.03. After Spearman's rank correlation test, ESR, sIgG4, and sIgG were independently associated with reduction of sIgG4 (p < .05) and were selected as input variables. Take into account these parameters, BP-ANN model was developed and the coefficient of determination (R² ) model was 0.95512.

CONCLUSION

The BP-ANN model based on ESR, sIgG4, and sIgG could predict the 3-month reduction of sIgG4 for IgG4-DS patients. It showed potential clinical application value.

New cardiac manifestation of IgG4-related disease: a case report

(IgG4-RD) is a systemic fibro-inflammatory immune-mediated disease, which has been defined in the past few years. IgG4-RD affects various organs and leads to a variety of clinical manifestations. As it is a relatively newly defined entity, new manifestations are now being recognised and reported. We describe a case involving the cardiovascular system.

[IGG4-related diseases in endocrinology]

Immunoglobulin-G4-related disease (IgG4-RD) is a chronic immunomediated pathology of different organs of local or systemic nature, which has been established as a separate clinical entity in the early 2000s and is characterized by storiform fibroid inflammation of the affected tissues, their increase, and elevated serum immunoglobulin-G4 (IgG4) levels. The most common manifestations of the disease are major salivary and lacrimal gland enlargement, lymphadenopathy and type 1 autoimmune pancreatitis (AIP1), however, other organs may be also involved (the thyroid, eyes, meninges, heart, lungs, kidneys, aorta, upper airways, mesentery, etc.). The effectiveness of treatment of IgG4-RD, as well as other pathological conditions, is also determined by the timely diagnosis. However, the latter is complicated due to the variety of clinical manifestations and rather variable diagnostic criteria. It is necessary to constantly update the evidence-based knowledge and diagnostic algorithms within this pathology in order to overcome the difficulties, and involve immunologists, endocrinologists, pathologists and specialists in other spheres. This review provides information about the etiology, pathogenesis, and current methods of diagnosis and treatment of IgG4-related diseases, as well as examples of some manifestations of IgG4-RD that an endocrinologist may face in practice.

Multiple Processes May Involve in the IgG4-RD Pathogenesis: An Integrative Study via Proteomic and Transcriptomic Analysis

Immunoglobulin G4-related disease (IgG4-RD) is a newly defined disease entity, while the exact pathogenesis is still not clear. Identifying the characters of IgG4-RD in proteomic and transcriptomic aspects will be critical to investigate the potential pathogenic mechanisms of IgG4-RD. We performed proteomic analysis realized with iTRAQ technique for serum samples from eight treatment-naive IgG4-RD patients and eight healthy volunteers, and tissue samples from two IgG4-RD patients and two non-IgG4-RD patients. Transcriptomic data (GSE40568 and GSE66465) was obtained from the GEO Dataset for validation. The weighted correlation network analysis (WGCNA) was applied to detect the gene modules correlated with IgG4-RD. KEGG pathway analysis was used to investigate pathways enriched in IgG4-RD samples. As a result, a total of 980 differentially expressed proteins (DEPs) in tissue and 94 DEPs in serum were identified between IgG4-RD and control groups. Three hundred fifty-four and two hundred forty-seven genes that most correlated with IgG4-RD were detected by WGCNA analysis in tissue and PBMC, respectively. We also found that DEPs in IgG4-RD samples were enriched in several immune-related activities including bacterial/viral infections and platelet activation as well as some immune related signaling pathways. In conclusion, we identified multiple processes/factors and several signaling pathways that may involve in the IgG4-RD pathogenesis, and found out some potential therapeutic targets for IgG4-RD.

Epidemiological features of immunoglobulin G4-related sclerosing cholangitis in Japan

BACKGROUND/PURPOSE

Epidemiological data on immunoglobulin G4-related sclerosing cholangitis (IgG4-SC) are scarce.

METHOD

We randomly selected healthcare facilities from a list of all facilities in Japan. The selection rate was determined according to a stratification based on the facility characteristics and scale. We sent questionnaires to the selected facilities enquiring about the number and sex of patients with IgG4-SC in 2018. Among responding facilities, we further inquired about the clinical characteristics of the patients with IgG4-SC.

RESULTS

We selected 1180 departments from health centers across Japan. Of them, 532 (45.1%) responded to the questionnaires. The number of reported patients with IgG4-SC was 1045, and the estimated point prevalence was 2.18 (95% confidence interval, 2.13-2.23) per 100 000 population. In addition, we enrolled 1096 patients with IgG4-SC, combining data from previously and newly registered patients. Male patients comprised 79.5% of the population and patients aged 60-80 years had the highest risk for developing the disease. The follow-up period was 5.1 ± 4.0 years and the 5- and 10-year overall survival rates were 95.3% and 89.0%, respectively.

CONCLUSIONS

The point prevalence of IgG4-SC was 2.18 per 100 000 population. The epidemiological features were similar to those observed in previous studies.

Immunoglobulin G4 (IgG4)-Related Sialadenitis and Dacryoadenitis With Chronic Rhinosinusitis

Immunoglobulin G4-related disease (IgG4-RD) is a new disease entity of rare and complex immune-mediated fibroinflammatory conditions that can affect any organ. The concomitance of IgG4 sclerosing sialadenitis and dacryoadenitis with rhinosinusitis is extremely rare. We report a case of IgG4 sclerosing sialadenitis and dacryoadenitis (Mikulicz's disease) diagnosed in a middle-aged African American man with a long-standing history of chronic rhinosinusitis who presented with progressively worsening bilateral salivary and lacrimal glands swelling. Imaging revealed pansinusitis, symmetric enlargement of the lacrimal glands, parotid glands, and submandibular glands. Serological IgG4 level was significantly elevated and the diagnosis of IgG4 sclerosing sialadenitis was confirmed by histopathology. A robust clinical response in the facial swelling and nasal manifestations was noted after the initiation of immunotherapy with corticosteroids.

Tumour of the orbit and pterygopalatine fossa: delayed recognition of possible IgG4-related disease

Introduction

IgG4-related disease (IgG4-RD) is a systemic fibrotic-inflammatory disease characterised by elevated serum concentration of IgG4 and tissue infiltration by plasma cells. IgG4-RD is a newly recognised fibro-inflammatory condition, characterised by organ mass lesions, special histopathological appearance, and - often but not always - elevated serum IgG4 concentrations. IgG4-RD is a separate, clinically distinct disease entity, but, due to its heterogeneous manifestation, it is a subject of interest of physicians of various specialties. Histopathological examination is the gold standard in the diagnosis.

Case report

In the paper we discuss the case of a 13-year-old patient who had been diagnosed with fully symptomatic IgG4-RD nine years after initial manifestation. Although IgG4-RD is diagnosed markedly more often in adults than in children, in this case report we would like to emphasise that the disease may also occur in paediatric patients, and it constitutes both a diagnostic and therapeutic challenge in this age group.

Conclusions

IgG4-RD is a poorly recognised disease, especially in the paediatric population. To the best of our knowledge, case reports on IgG4-RD in paediatric patients available in the literature are sparse. The non-specific and heterogeneous manifestation may hinder the diagnostic process, and in some cases the disease is diagnosed accidentally, especially when it is asymptomatic. Since 2015, the first-line treatment in IgG4-RD has been glucocorticoids; however, combination therapies should not be underestimated as another method to achieve permanent remission.

Immunoglobulin G4-Related Hypertrophic Pachymeningitis of the Spine: A Case Report and Systematic Review of the Literature

BACKGROUND

Spinal immunoglobulin G4-related hypertrophic pachymeningitis (IgG4-HP) is a rare disease. Little information is known regarding the diagnosis, management, and prognosis of patients with spinal IgG4-HP.

METHODS

The authors present a case of spinal IgG4-HP with a systematic review of the literature according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Relevant studies (up to April 2020) that reported patients with spinal IgG4-HP, based on the criteria of Japan College of Rheumatology, were identified from the PubMed and Cochrane Library databases.

RESULTS

This systematic review identified 33 patients, including the present case, of whom 21 were male and 12 were female. The mean value of age was 51.2 (±12.6) years. Eight patients had systemic involvement. In addition, among 33 patients, 13 patients had an elevated serum IgG4. Surgery was performed in 31 patients. Steroid therapy alone and steroid therapy with immunosuppressants were effective in 94% and 100% of the cases, respectively. Furthermore, 31 of 33 patients reported improved outcomes, 1 patient died due to infection, and in 2 patients the data were not available.

CONCLUSIONS

Spinal IgG4-HP is a rare entity. In addition, it should be considered in the differential diagnosis of space-occupying lesions around the spinal cord. Histopathology with immunohistochemistry results provides the most reliable evidence for diagnosis. Steroid therapy is the first line of treatment. Surgical decompression may be required in patients presenting with nerve root and/or spinal cord compression. Long-term follow-up is necessary for patients with spinal IgG4-HP.

Multi-organ IgG4-related disease continues to mislead clinicians: A case report and literature review

BACKGROUND

Immunoglobulin G4-related disease (IgG4-RD) is a multisystemic mass forming immune-mediated disease that affects almost every organ and is a diagnostic challenge for every clinician. There is a lack of adequate epidemiological data worldwide, and evidence-based treatment recommendations are not yet established. We report the first case of IgG4-RD from Lithuania and the Baltic Sea region presented with thyroiditis, orbital myositis, orbitopathy, uveitis, scleritis, sialadenitis, autoimmune pancreatitis and prostatitis.

CASE SUMMARY

A 54-year-old Caucasian male was admitted to our tertiary Centre complaining of severe weight loss, diarrhoea, abdominal pain, salivary gland swelling, sicca symptoms and diplopia. On examination, bilateral palpable masses in the projection of major salivary glands, severe protrusion of the left eyeball and cachexia were noted. The patient was previously diagnosed with autoimmune thyroiditis and endocrine ophthalmopathy. The magnetic resonance imaging (MRI) of the head revealed enlarged extraocular muscles indicating orbital myositis. The biopsy from the salivary gland mass indicated sialadenitis. Abdominal MRI showed signs of autoimmune pancreatitis, and a serological test revealed the elevated serum IgG4 concentration. The patient was then diagnosed with IgG4-RD and successfully treated with prednisolone. There was a significant clinical, serological and radiological improvement after one month of treatment and no signs of relapse within twenty months. However, it took almost 18 years and the efforts of eight different medical specialists to establish the correct diagnosis.

CONCLUSION

A comprehensive approach to the patient is essential to improving the recognition of rare immune system conditions, such as IgG4-RD.

Hemochromatosis and Hepatocellular Carcinoma Secondary to Immunoglobulin G4-Related Disease with Hepatopathy: A Case Report

Immunoglobulin G4-related disease (IgG4-RD) is a recently characterized illness in which lymphocytes and plasma cells infiltrate various anatomical sites. IgG4-hepatopathy, a manifestation of IgG4-RD, is a broader term covering various patterns of liver injury. The clinical course, including the malignant potential of IgG4-RD, remains unclear. Here we report the first case of secondary hemochromatosis and hepatocellular carcinoma (HCC) developing from IgG4-hepatopathy. A 67-year-old man was admitted to our hospital for treatment of deteriorating glucose tolerance. Blood test results showed hypergammaglobulinemia, especially IgG4. He was readmitted 2 months later with dyspnea due to lung disease and pleural effusion, and elevated transaminase levels. He underwent liver and lung biopsies. IgG4-RD was diagnosed and he was treated with steroid therapy, which improved serum IgG4 levels and imaging abnormalities. A follow-up computed tomography (CT) scan conducted 38 months later revealed a tumor (diameter, 50 mm) in liver segments 7 and 8. The resected specimen revealed HCC and abundant siderosis in the background liver, indicating a diagnosis of hemochromatosis. IgG4-positive cells were scarce, probably because of corticosteroid therapy. In the present case, IgG4-RD was well controlled with prednisolone (PSL) and an immunosuppressive agent, and chronic hepatitis was not severe, even though the patient subsequently developed HCC. However, extensive siderosis consistent with hemochromatosis was unexpectedly noted. These findings suggest that secondary hemochromatosis and HCC developed during IgG4-RD with hepatopathy. We believe this case sheds light on IgG4-RD.

IgG4-related disease in the abdomen and pelvis: atypical findings, pitfalls, and mimics

IgG4-related disease (IgG4-RD) is a systemic, autoimmune, fibroinflammatory disease that can cause multi-organ damage. Although there have been many trials and studies since its recognition in 2003, there is still much that is unknown. Furthermore, IgG4-RD can affect any organ in the body and often has many mimics and alternative diagnoses, which can make for a challenging workup. Imaging plays a substantial role in the diagnosis of IgG4-RD and is often the first occasion where IgG4-RD comes into consideration. Thus, knowledge about the imaging findings of various manifestations of IgG4-RD can aid in the diagnosis and have a significant impact on patient management. In this article, we review the wide array of imaging findings, both typical and atypical, as well as possible mimics of IgG4-RD in the abdomen and pelvis.

[IgG4-related disease: Diagnostic criteria evolution toward the 2019 ACR/EULAR classification criteria]

The concept of IgG4-related disease (IgG4-RD) has recently been individualized in the early 2000s, but most of the organ involvements are known since more than 100 years. IgG4-RD is a non-malignant fibroinflammatory disorder, characterized by peculiar immunological and pathological abnormalities, which can affect virtually all organs or tissues. Diagnostic criteria have been proposed and have evolved rapidly, with general or organ specific criteria. An international and multidisciplinary group assembled by the American College of Rheumatology (ACR) and the European League Against Rheumatism (EULAR) has recently developed and validated a set of classification criteria called 2019 ACR/EULAR classification criteria for IgG4-related disease. The objective of this review is to discuss the evolution from organ specific and general diagnostic criteria toward the 2019 ACR/EULAR classification criteria, as well as respective benefits and limits of these criteria. The use of the 2019 ACR/EULAR classification criteria will help to better define homogeneous group of IgG4-RD patients in future clinical, epidemiological and basic science research studies on the disease.

A Case of an IgG4-Related Disease Mimicking Malignancy and Resolving With Steroids

A 77-year-old African American female was referred to oncology for evaluation of an adrenal fossa mass detected on computed tomography scan of the abdomen and pelvis (CT-scan A/P) that was ordered as a work-up for painless hematuria. Further evaluation by positron emission tomography (PET) scan showed hypermetabolic masses in the left suprarenal and right iliac region. The biopsy of the right iliac mass was consistent with IgG4-related disease (IgG4RD). It was supported by an elevated serum IgG4 level. She was treated with prednisone with a good response.

Differential diagnosis between pancreatic involvement in IgG4-related disease and pancreatic cancer

IgG4-related disease is a systemic disorder characterised by diffuse or tumoural inflammatory lesions. It can mimic pancreatic cancer, leading to errors in diagnosis and treatment increasing rates of morbidity and mortality in patients. The aim of this review is to take a differential diagnostic approach to these two entities using epidemiology, clinical and laboratory findings, imaging and histopathology.

Vasculitis beyond aortitis in IgG4-related disease (IgG4-RD): case report and review of the literature

IgG4-related disease (IgG4-RD) can affect almost every tissue/organ. Vascular involvement in the setting of IgG4-RD is increasingly being recognized with most of the cases pertaining patients with aortitis and/or periaortitis with or without aneurysm formation. However, it is now evident that other vessels like iliac arteries, coronary arteries, carotids, and others can also be affected being often underdiagnosed. Vascular involvement is expressed as vessel wall thickening, while aneurysm formation is also occasionally seen. Although histopathological findings are the cornerstone in the diagnosis of IgG4-RD, imaging modalities like magnetic resonance imaging (MRI) and positron emission tomography (PET) are similarly important when vascular involvement occurs, helping in the mapping of the disease and in identifying other, more accessible to biopsy, affected organs. Inflammation markers like erythrocyte sedimentation rate and C-reactive protein have also been described in IgG4-RD patients with vascular involvement. Herein, we present a case of a middle-aged man with long-term high inflammation markers who eventually diagnosed with IgG4-RD after an ascending aorta aneurysm operation, while a subsequent comprehensive magnetic resonance angiography revealed also involvement of the abdominal aorta and the left subclavian and left common carotid. Moreover, we sought to review the current literature about medium- and large-vessel involvement, beyond the aorta, in patients with IgG4-RD.

Orbital Rosai-Dorfman disease initially diagnosed as IgG4-related disease: a case report

Inflammatory orbital lesions include a broad list of diagnoses, many of them with overlapping clinical and radiographic features. They often present a diagnostic conundrum, even to the most experienced orbital specialist, thus placing considerable weight on surgical biopsy and histopathological analysis. However, histopathological diagnosis is also inherently challenging due to the rarity of these lesions and the overlaps in histologic appearance among distinct disease entities. We herein present the case of an adolescent male with a subacutely progressive orbital mass that generated a significant diagnostic dilemma. Early orbital biopsy was consistent with a benign fibro-inflammatory lesion, but corticosteroid therapy was ineffective in halting disease progression. After an initial substantial surgical debulking, histopathological analysis revealed several key features consistent with IgG4-related disease (IgG4-RD), a systemic fibro-inflammatory process typically accompanied by multifocal tumor-like lesions. Surprisingly, within months, there was clear evidence of clinical and radiographic disease progression despite second-line rituximab treatment, prompting a second surgical debulking. This final specimen displayed distinctive features of Rosai-Dorfman disease (RDD), a systemic inflammatory disease characterized by uncontrolled histiocytic proliferation. Interestingly, certain features of this re-excision specimen were still reminiscent of IgG4-RD, which not only reflects the difficulty in differentiating RDD from IgG4-RD in select cases, but also illustrates that these diagnoses may exist along a spectrum that likely reflects a common underlying pathogenetic mechanism. This case emphasizes the importance of surgical biopsy or resection and histopathological analysis in diagnosing—and, ultimately, treating—rare, systemic inflammatory diseases involving the orbit, and, furthermore, highlights the shared histopathological features between RDD and IgG4-RD.

A Case With IgG4-Related Spinal Pachymeningitis Causing Spinal Cord Compression

Immunoglobulin G4 (IgG4)-related disease is a systemic disease characterized by sclerosing lesions and an increased serum IgG4 level. This condition can involve any organ, but IgG4-related spinal pachymeningitis is relatively rare. In the current study, we report a case of spinal cord compression caused by IgG4-related spinal pachymeningitis. A 39-year-old man presented to us with a 15-day history of back pain and a 3-day history of dysuresia, exacerbated by weakness in the lower extremities for 2 days. Cervical magnetic resonance imaging (MRI) showed strip-shaped abnormal signals along the anterior and posterior borders of the spinal cord at the C5–T4 levels. The IgG level in cerebrospinal fluid was 718.0 mg/L. Thoracic MRI revealed strip-shaped abnormal signals with remarkable enhancement along the anterior and posterior borders of the dural sac at the T1–T6 levels. Histopathological examination confirmed IgG4-related spinal pachymeningitis. The symptoms worsened rapidly, and surgical resection of the space-occupying lesion in the vertebral canal was performed for spinal decompression. Corticosteroid therapy was administered, and the patient's motor functions were mildly improved. IgG4-related disease can manifest as spinal pachymeningitis and cause spinal cord compression. Clinicians should be aware of this rare condition, and early diagnosis, timely surgical decompression, and appropriate corticosteroid therapy should be highlighted.

Comparison of the Effects of Cyclophosphamide and Mycophenolate Mofetil Treatment Against Immunoglobulin G4-Related Disease: A Retrospective Cohort Study

Background: Although there are multiple ways to manage immunoglobulin G4-related disease (IgG4-RD), including treatment with glucocorticoids, "steroid-sparing" immunosuppressive drugs, or biologic agents, few clinical trials on IgG4-RD have been conducted. This study aimed to compare the efficacy and safety of glucocorticoids (GCs) combined with cyclophosphamide (CYC) or mycophenolate mofetil (MMF) in IgG4-RD patients. This cohort study was registered at ClinicalTrials.gov (ID: NCT01670695). Methods: This retrospective study included 155 IgG4-RD patients who received GCs with CYC or MMF at the Department of Rheumatology at Peking Union Medical College Hospital between January 2012 and July 2018. Propensity score matching (PSM) was conducted to match two groups of patients based on their baseline clinical characteristics. Treatment response, relapse rate, and drug safety were analyzed. The treatment response was evaluated based on complete response (CR), partial response (PR), and no change (NC), and the cumulative relapse rate and adverse events in each treatment group were compared using Kaplan-Meier curves and log-rank test, respectively. Results: Of the 155 IgG4-RD patients, 90 were treated with GCs plus CYC (group I) and 65 with GCs plus MMF (group II). After propensity score-matched (PSM) analysis, 108 patients were selected (54 in each group), 49 of whom had "definite" IgG4-RD, 8 "probable" IgG4-RD, and 51 "possible" IgG4-RD. At the last follow-up, the total response in groups I and II was 98.15 and 96.3%, respectively, and within 12 months, the cumulative relapse rate in group II was significantly higher than that in group I (14.8 vs. 3.7%, P = 0.046). Recurrence occurred at the paranasal sinus, lacrimal glands, skin, lung, pancreas, and bile ducts, and the relapsed patients achieved remission after switching immunosuppressants or/and increasing the GC dose. Conclusions: In IgG4-RD patients with internal organ involvement, GCs plus CYC or MMF are both effective with similar effects in disease response, while GCs plus CYC reduced the relapse rate better than GCs plus MMF.

Occurrence of Immunoglobulin G4-related Disease during Chemotherapy for Advanced Breast Cancer

Immunoglobulin G4-related disease (IgG4-RD) is defined as an inflammatory lymphoproliferative disorder. The relationship between malignancies and IgG4-RD remains unclear. We herein present a case of IgG4-RD that occurred during chemotherapy for advanced breast cancer. In this case, it was challenging to determine which of these diseases was responsible for the patient's mediastinal lymphadenopathy. Lymphadenopathy with IgG4-RD was diagnosed by assessing the reactivity to corticosteroids, which were used as premedication in chemotherapy, over time. The administration of prednisolone, which was initiated to treat active IgG4-RD, led to stable systemic therapy for malignancy. It is imperative to assess the disease activity and consider each treatment.

European Guideline on IgG4-related digestive disease - UEG and SGF evidence-based recommendations

The overall objective of these guidelines is to provide evidence-based recommendations for the diagnosis and management of immunoglobulin G4 (IgG4)-related digestive disease in adults and children. IgG4-related digestive disease can be diagnosed only with a comprehensive work-up that includes histology, organ morphology at imaging, serology, search for other organ involvement, and response to glucocorticoid treatment. Indications for treatment are symptomatic patients with obstructive jaundice, abdominal pain, posterior pancreatic pain, and involvement of extra-pancreatic digestive organs, including IgG4-related cholangitis. Treatment with glucocorticoids should be weight-based and initiated at a dose of 0.6-0.8 mg/kg body weight/day orally (typical starting dose 30-40 mg/day prednisone equivalent) for 1 month to induce remission and then be tapered within two additional months. Response to initial treatment should be assessed at week 2-4 with clinical, biochemical and morphological markers. Maintenance treatment with glucocorticoids should be considered in multi-organ disease or history of relapse. If there is no change in disease activity and burden within 3 months, the diagnosis should be reconsidered. If the disease relapsed during the 3 months of treatment, immunosuppressive drugs should be added.

Rosai-Dorfman disease: an overview

CONTEXT

Rosai-Dorfman disease is an uncommon histiocytic disorder most frequently presenting as bilateral cervical lymphadenopathy in children and young adults. Extranodal disease occurs in a significant proportion of patients. It has been recently classified as part of the 'R group' of histiocytoses by the Histiocyte Society in 2016. Cutaneous Rosai-Dorfman disease is regarded as a separate disease entity that falls into the 'C group' of histiocytoses according to this classification system. The pathogenesis was previously poorly understood; however, recent evidence demonstrating clonality in a subset of cases raises the possibility of a neoplastic process. A possible association with IgG4-related disease remains controversial.

OBJECTIVES

To provide a comprehensive review of Rosai-Dorfman disease, including nodal, extranodal and cutaneous forms, with a particular emphasis on new insights into the possible clonal nature of the disease; to discuss the recently revised classification of the histiocytoses by the Histiocyte Society; and to summarise the findings from the literature regarding the controversial association with IgG4-related disease.

DATA SOURCES

This review is based on published peer-reviewed English literature.

CONCLUSIONS

Classic Rosai-Dorfman disease, which may be sporadic or familial, is considered a separate entity from cutaneous disease, which is reflected in the revised classification of histiocytoses. An increase in IgG4-positive plasma cells may be seen in Rosai-Dorfman disease. This finding in isolation is of limited significance and should be interpreted with caution. Studies investigating the molecular profile of the disease show that in at least a subset of cases the disease is a clonal process. The classification of Rosai-Dorfman disease is therefore likely to change as our understanding of the aetiopathogenesis evolves.

IgG4-related disease mimicking renal pelvis tumor with peritoneal carcinomatosis

IgG4-RD may rarely present as a retroperitoneal fibrosis, mimicking carcinomatosis. Clinicians should consider this disease when encountering an idiopathic peritoneal and retroperitoneal fibrosis with renal involvement and hydronephrosis.

Advances in the diagnosis and management of IgG4 related disease

IgG4 related disease was recognized as a unified disease entity only 15 years ago. Awareness of IgG4 related disease has increased worldwide since then, and specialists are now familiar with most of its clinical manifestations. Involvement of the pancreato-biliary tract, retroperitoneum/aorta, head and neck, and salivary glands are the most frequently observed disease phenotypes, differing in epidemiological features, serological findings, and prognostic outcomes. In view of this multifaceted presentation, IgG4 related disease represents a great mimicker of many neoplastic, inflammatory, and infectious conditions. Histopathology remains key to diagnosis because reliable biomarkers are lacking. Recently released classification criteria will be invaluable in improving early recognition of the disease. IgG4 related disease is highly treatable and responds promptly to glucocorticoids, but it can lead to end stage organ failure and even death if unrecognized. Prolonged courses of corticosteroids are often needed to maintain remission because the disease relapses in most patients. Rapid advancement in our understanding of the pathophysiology of IgG4 related disease is leading to the identification of novel therapeutic targets and possible personalized approaches to treatment.

Immunoglobulin G4-related spinal pachymeningitis

Immunoglobulin G4-related disease (IgG4-RD) is rare disease entity and has recently been recognized as an inflammatory disorder with the tendency to affect multiple organs. Pachymeningitis of spine caused by IgG4-related disease is extremely rare. Neck pain and spinal cord compression symptoms consist of usual presentation of IgG4-related spinal pachymeningitis; however, polyarthritis is an unusual presentation of this disease, and it was reported in only one case that mimicked psoriatic arthritis. In this report, we describe a case of IgG4-related spinal pachymeningitis in a middle-age male who presented initially with neck pain and rheumatoid arthritis-like symptoms and later on developed both right upper and lower limb weakness. He was found to had pachymeningeal thickening on a cervical magnetic resonance image (MRI) and elevated serum IgG4 levels. He was treated with glucocorticoids and rituximab, which led to a significantly positive radiological response.

Mimickers of pulmonary lymphoma

There are multiple entities that involve the lung that have radiographic, clinical, and morphologic overlaps with pulmonary lymphoma. In this review, we will discuss these entities in detail and provide relevant updates.

[IgG4-related disease: what do we know after 20 years]

IgG4-related disease is immunomediated fibroinflammatory condition, characterized by tumefective lesions in different organs with distinctive pathomorphological features and IgG4 hypersecretion in serum and tissues in the majority of patients. IgG4-RD has been established as a separate clinical in the early 2000s. In the review we focus on the evolution of views on ethiopathogenesis of the disease, therapeutic and diagnostic options and classification of the disease.