IgG4-related disease: a systematic review of this unrecognized disease in pediatrics

Sex as a predictor of clinical phenotype and determinant of immune response in IgG4-related disease: a retrospective study of patients fulfilling the American College of Rheumatology-European League Against Rheumatism classification criteria

BACKGROUND

IgG4-related disease is a multiorgan fibroinflammatory disease considered to have an autoimmune origin. Case series describing individual organ involvement have suggested differences in phenotypic expression between males and females. We aimed to characterise differences in IgG4-related disease manifestations between male and female patients in a large single-centre cohort.

METHODS

In this retrospective, single-centre cohort study, patients were recruited from the Massachusetts General Hospital Rheumatology Clinic (Boston, MA, USA) and classified according to the American College of Rheumatology-European Alliance of Associations for Rheumatology (ACR-EULAR) classification criteria. Only patients satisfying the ACR-EULAR classification criteria were included in the study. Data on age at diagnosis, organ involvement at baseline, treatment status, and pre-treatment laboratory values were collected. Circulating plasmablasts and B-cell subsets were quantitated by flow cytometry. Active disease was defined by an IgG4-related disease Responder Index score of more than 0. Laboratory values were analysed for patients who were untreated at baseline and had active IgG4-related disease. The main outcomes were assessed in all participants with available data.

FINDINGS

Of the 564 participants enrolled in the Massachusetts General Hospital Rheumatology Clinic IgG4-related disease Registry, 328 fulfilled ACR-EULAR classification criteria and were included between January, 2008, and May, 2023. There was a strong male predominance (male:female ratio 2·2:1) with 226 (69%) males and 102 (31%) females, which contrasted markedly with our general rheumatology clinic population (0·4:1; p<0·001). The male predominance increased with each decade of life starting at age 40 years. On average, male patients were 5·5 years older at diagnosis than female patients (63·7 years vs 58·2 years; p=0·0031). We observed male patients to have higher ACR-EULAR classification criteria scores at baseline with a median score of 35·0 (IQR 28·0-46·0), compared with 29·5 (25·0-39·0) for females (p=0·0010). The proportion of male patients with pancreatic and renal involvement was almost double the proportion observed in female patients (50% of the male patients had pancreatic involvement, compared with about 26% of the female patients; p<0·0001). Male patients were more likely to have serological abnormalities at baseline. The distribution of IgG4 values differed significantly between male an female sexes, favouring higher values in males. We found that male patients with IgG4-related disease were more likely to have active B-cell responses in the blood as defined by plasmablast expansions.

INTERPRETATION

IgG4-related disease is unusual among autoimmune diseases in that it is more likely to affect males than females and to present with a striking sex-dependent organ distribution and degree of B-cell response. These findings highlight important variation between IgG4-related disease and other conditions generally believed to have an autoimmune basis. Most autoimmune diseases, by contrast to IgG4-related disease, demonstrate pronounced predilections for affecting females more frequently than males. Hypotheses surrounding the cause and pathophysiology of this condition need to consider this unusual sex distribution among patients with IgG4-related disease.

FUNDING

National Institutes of Health, National Institute of Allergy and Infectious Diseases, Rheumatology Research Foundation, and the National Institute of Arthritis and Musculoskeletal and Skin Diseases.

18 F-FDG PET/CT in Pediatric Immunoglobulin G4-Related Disease

ABSTRACT

A 14-year-old boy presented with severe, nonintentional weight loss, fatigue, and cough. Investigations were notable for raised inflammatory markers and significantly elevated serum immunoglobulin G4 (IgG4). 18 F-FDG PET/CT was obtained for assessment of disease involvement and extent, to exclude differential diagnoses and to guide biopsy. The study demonstrated extensive FDG-avid nodal disease and multisystem organ involvement. Excisional biopsy of a right inguinal lymph node demonstrated reactive changes with numerous IgG4-positive plasma cells consistent with IgG4-related disease. He was commenced on immunosuppressive therapy with consequent weight restoration and symptom resolution.

IgG4-related disease-rare but you should not forget it

Immunoglobulin G4-related disease is a systemic immune-mediated disease with insidious evolution characterized by fibroinflammatory lesions over virtually any organ system. Despite the remarkable progression of knowledge, its etiology remains undefined. Due to its relapse-remitting pattern, it could accumulate irreversible damage, increasing comorbidities and mortality. This paper emphasizes key concepts for diagnosing and treating patients with this condition.

When inflammation is not just inflammation-A review of systemic diseases of the nose and sinuses part 1: IgG4-related disease and sarcoidosis

BACKGROUND

Chronic rhinosinusitis is a very common condition. IgG4-related disease (IgG4-RD) and sarcoidosis are systemic diseases which can contribute to the development of chronic rhinosinusitis in select patients.

OBJECTIVE

Characterize the presenting features, diagnostic criteria, workup, and management of sinonasal IgG4-RD and sarcoidosis as they are encountered in otolaryngology clinics.

METHODS

Full length manuscripts published 2000 or later were reviewed. A separate search was conducted for each disease. Pertinent clinical features related to sinonasal manifestations of IgG4-RD and sarcoidosis were collected and reported in this review.

RESULTS

404 references were discovered during literature review process. In total, 42 references for IgG4-RD and 34 references for sarcoidosis were included in this review.

CONCLUSION

IgG4-RD and sarcoidosis are autoimmune inflammatory conditions that can affect many systems of the body. For both disease entities, sinonasal disease is a less common presentation which can lead to delayed diagnosis. Sinonasal IgG4-RD commonly presents in the setting of multisystem disease. All with other clinical features, biopsy plays a key role in the diagnosis for both diseases. Treatment for IgG4-RD consists primarily of steroids and rituximab which can lead to excellent and durable remission. A variety of immunosuppressive agents are used in the management of sarcoidosis. Surgery for IgG4-RD is primarily utilized for tissue biopsy, although resection or debulking may be considered. For sarcoidosis, surgery can be used for tissue biopsy and functional sinus surgery can offer symptomatic relief in many patients.

A case report of IgG4-related hepatic inflammatory pseudotumor in a 3-year old boy

Background

Hepatic Inflammatory Pseudotumor (IPT) is an infrequent condition often masquerading as a malignant tumor, resulting in misdiagnosis and unnecessary surgical resection. The emerging concept of IgG4-related diseases (IgG4-RD) has gained widespread recognition, encompassing entities like IgG4-related hepatic IPT. Clinically and radiologically, corticosteroids and immunosuppressive therapies have proven effective in managing this condition.

Case Presentation

A 3-year-old Chinese boy presented to the clinic with an 11-month history of anemia, fever of unknown origin, and a tender hepatic mass. Blood examinations revealed chronic anemia (Hb: 6.4 g/L, MCV: 68.6 fl, MCH: 19.5 pg, reticulocytes: 1.7%) accompanied by an inflammatory reaction and an elevated serum IgG4 level (1542.2 mg/L). Abdominal contrast-enhanced computed tomography unveiled a 7.6 cm low-density mass in the right lateral lobe, while magnetic resonance imaging demonstrated slight hypointensity on T1-weighted images and slight hyperintensity on T2-weighted images, prompting suspicion of hepatic malignancy. A subsequent liver biopsy revealed a mass characterized by fibrous stroma and dense lymphoplasmacytic infiltration. Immunohistochemical analysis confirmed the presence of IgG4-positive plasma cells, leading to the diagnosis of IgG4-related hepatic IPT. Swift resolution occurred upon initiation of corticosteroid and mycophenolate mofetil therapies.

Conclusion

This study underscores the diagnostic approach to hepatic IPT, utilizing histopathology, immunostaining, imaging, serology, organ involvement, and therapeutic response. Early histological examination plays a pivotal role in clinical guidance, averting misdiagnosis as a liver tumor and unnecessary surgical interventions.

Are Gender Differences Important for Autoimmune Liver Diseases?

Gender Medicine has had an enormous expansion over the last ten years. Autoimmune liver diseases include several conditions, i.e., autoimmune hepatitis (AIH), primary biliary cholangitis (PBC), primary sclerosing cholangitis (PSC), and conditions involving the liver or biliary tree overlapping with AIH, as well as IgG4-related disease. However, little is known about the impact of sex in the pathogenesis and natural history of these conditions. The purpose of this review is to provide an update of the gender disparities among the autoimmune liver diseases by reviewing the data published from 1999 to 2023. The epidemiology of these diseases has been changing over the last years, due to the amelioration of knowledge in their diagnosis, pathogenesis, and treatment. The clinical data collected so far support the existence of sex differences in the natural history of autoimmune liver diseases. Notably, their history could be longer than that which is now known, with problems being initiated even at a pediatric age. Moreover, gender disparity has been observed during the onset of complications related to end-stage liver disease, including cancer incidence. However, there is still an important debate among researchers about the impact of sex and the pathogenesis of these conditions. With this review, we would like to emphasize the urgency of basic science and clinical research to increase our understanding of the sex differences in autoimmune liver diseases.

ANCA-associated kidney disease preceded by orbital pseudotumor

INTRODUCTION

Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) and IgG4-related disease (IgG4-RD) are distinct immune disorders with overlapping clinical and laboratory features. While ANCA positivity excludes IgG4-RD in the 2019 ACR/EULAR classification, this criterion is not uniformly applied, and AAV can form inflammatory masses in various organs and show increase in IgG4 + plasma cells, similar to IgG4-RD.

CASE DIAGNOSIS/TREATMENT

A 5-year-old female with history of orbital mass diagnosed as IgG4-RD presents with acute kidney injury. She has a myeloperoxidase ANCA, and kidney biopsy shows pauci-immune crescentic glomerulonephritis and acute tubulointerstitial nephritis with increased IgG4 + plasma cells and tubular basement membrane (TBM) deposits.

CONCLUSION

In isolation, TBM deposits and increased IgG4 + plasma cells are suggestive of IgG4-RD. In the context of a positive ANCA and pauci-immune crescentic glomerulonephritis, however, increased IgG4 + plasma cells due to AAV are favored. In cases with features of IgG4-RD, ANCA positivity suggests an alternate diagnosis of AAV to be more likely.

Chronic sclerosing sialadenitis of the bilateral submandibular glands in childhood - a diagnostic dilemma

Chronic sclerosing sialadenitis (CSS), currently included in the group of immunoglobulin G4 (IgG4)-related diseases, is an under-recognized inflammatory lesion that afflicts mostly the submandibular gland of 40-60 years adults. To our knowledge, only one case of CSS located in the submandibular gland has been reported in childhood to date. We present a case of CSS in a 5-year-old male child. He presented with bilateral submandibular swellings that clinically resembled discrete lumps, suspected to be tumors. The completely resected tumors composed predominantly of dense lymphoplasmacytic inflammatory infiltrate rich in IgG4-positive cells [77-90 IgG(+) cells per high-power field; IgG4(+)∕IgG(+) cells ratio of 42.77%]. We discuss the peculiarities of this case, and we also review the literature on CSS.

Pediatric IgG4-related disease: a descriptive review

INTRODUCTION

IgG4-related disease (IgG4-RD) is an immune-mediated systemic fibroinflammatory condition characterized by serum IgG4 elevation and IgG4-positive plasma cell infiltration into various organs. It generally occurs in elderly males. Pediatric cases have been reported, albeit rarely, accordingly lack of recognition of such cases could delay therapeutic intervention leading to poorer outcomes.

AREAS COVERED

The present review is a descriptive review of all published case reports, cohort studies, and reviews of pediatric IgG4-RD listed in PubMed. Characteristics of pediatric IgG4-RD were clarified, including sex, organ involvement, serological and histological findings, and treatment. We assessed how many published cases met current classification and comprehensive diagnostic criteria.

EXPERT OPINION

The characteristics of pediatricIgG4-RD differed from adult IgG4-RD in terms of sex and involved organs. There was no clear male dominance in numbers of cases, and surface organ involvement such as ophthalmic diseases were more common in the pediatric IgG4-RD. Organ involvement tended to be indolent and unilateral, causing difficulty in definitively diagnosing pediatric IgG4-RD. Only about 20% of published cases met IgG4-RD classification or comprehensive diagnostic criteria. Physicians should be careful in diagnosing pediatric IgG4-RD after excluding mimickers. International collaboration toward high-quality evidence to support diagnosis and treatment of pediatric IgG4-RD is advised.

Increased IgG4+ plasma cells are common in excised lymph nodes from children and adolescents without IgG4-related disease

Lymphadenopathy is a common finding in patients with IgG4-related disease (IgG4-RD) and often associated with increased IgG4+ plasma cells in this setting. The histologic features of so-called IgG4-related lymphadenopathy (IgG4-LAD) have seldom been investigated in children and adolescents, and step-wise progression to extranodal IgG4-RD has not been described. This study was performed to further evaluate the frequency, pathologic features, and clinical significance of IgG4-LAD-like histologic changes in the pediatric setting. We analyzed 37 benign lymph nodes collected semi-consecutively from children aged 0-18 years at our institution for both absolute and relative IgG4+ plasma cell abundance and recurrent histomorphologic patterns associated with IgG4-LAD. The combination of IgG4+/IgG+ plasma cell ratio >40% and IgG4+ plasma cell count ≥50 were considered as IgG4-LAD-like per expert consensus guidelines. Seven cases (19%) met both diagnostic criteria. The dominant histomorphologic patterns were follicular hyperplasia (n = 6), interfollicular expansion (n = 3), and progressive transformation of germinal centers (n = 3). Extranodal manifestations of IgG4-RD were not identified in this cohort (38 months average follow-up). Instead, clinical and laboratory findings indicated that lymph node enlargement in most patients could likely be attributed to alternative processes including antecedent dentistry, concurrent infection, and incipient Crohn's disease. Our findings suggest that the histologic features of IgG4-LAD are likely much more common in children and adolescents than previously recognized, often existing in complex with common reactive lymphadenopathies. The diagnostic value of routine immunohistochemical assessment for IgG4+ plasma cells in benign lymph nodes from pediatric patients without established extranodal IgG4-RD and/or other supportive clinical and laboratory data is therefore uncertain.

IgG4-related cholangitis - a mimicker of fibrosing and malignant cholangiopathies

IgG4-related cholangitis (IRC) is the major hepatobiliary manifestation of IgG4-related disease (IgG4-RD), a systemic fibroinflammatory disorder. The pathogenesis of IgG4-RD and IRC is currently viewed as multifactorial, as there is evidence of a genetic predisposition while environmental factors, such as blue-collar work, are major risk factors. Various autoantigens have been described in IgG4-RD, including annexin A11 and laminin 511-E8, proteins which may exert a partially protective function in cholangiocytes by enhancing secretion and barrier function, respectively. For the other recently described autoantigens, galectin-3 and prohibitin 1, a distinct role in cholangiocytes appears less apparent. In relation to these autoantigens, oligoclonal expansions of IgG4+ plasmablasts are present in patients with IRC and disappear upon successful treatment. More recently, specific T-cell subtypes including regulatory T cells, follicular T helper 2 cells, peripheral T helper cells and cytotoxic CD8+ and CD4+ SLAMF7+ T cells have been implicated in the pathogenesis of IgG4-RD. The clinical presentation of IRC often mimics other biliary diseases such as primary sclerosing cholangitis or cholangiocarcinoma, which may lead to inappropriate medical and potentially invalidating surgical interventions. As specific biomarkers are lacking, diagnosis is made according to the HISORt criteria comprising histopathology, imaging, serology, other organ manifestations and response to therapy. Treatment of IRC aims to prevent or alleviate organ damage and to improve symptoms and consists of (i) remission induction, (ii) remission maintenance and (iii) long-term management. Glucocorticosteroids are highly effective for remission induction, after which immunomodulators can be introduced for maintenance of remission as glucocorticosteroid-sparing alternatives. Increased insight into the pathogenesis of IRC will lead to improved diagnosis and novel therapeutic strategies in the future.

Infectious and Inflammatory Processes of the Orbits in Children

Most primary orbital pathology in children is due to bacterial infection. Radiologists typically encounter these cases to evaluate for clinically suspected postseptal orbital involvement. Contrast-enhanced cross-sectional imaging is important for the detection and early management of orbital infection and associated subperiosteal/orbital abscess, venous thrombosis, and intracranial spread of infection. Benign mass-like inflammatory processes involving the pediatric orbit are rare, have overlapping imaging features, and must be distinguished from orbital malignancies.

[The clinical case of IgG4-related thyroid disease in a 6-year-old child]

IgG4-related disease is a rare chronic pathology manifested by lymphoplasmacytic infiltration of one or more organs, the formation of storiform fibrosis, tissue edema, and an increase of IgG4 in the blood. This disease was singled out as an independent nosological unit only in 2001. The incidence is less than 1 in 100,000 people per year. Almost any organ can be affected in IgG4-related disease. The association of Riedel's thyroiditis with IgG4 was established in 2010. Riedel's thyroiditis is an extremely rare inflammatory disease of the thyroid gland, which diagnosis is complicated by an atypical course and the absence of characteristic symptoms. Less than 300 clinical cases of the disease have been described in the world, only two from them were in children. This article presents a clinical case of a 6-year-old boy with Riedel's thyroiditis.

Inflammatory Diseases of the Eye, Bowel, and Bone in Children

Pediatric rheumatological diseases present with diverse manifestations affecting various tissues and organs. Though most childhood illnesses with immune dysregulation affect multiple organs or systems simultaneously or gradually, few inflammatory conditions affect certain organs as distinguished primary targets. Pediatric inflammatory diseases of the eye, bowel, and bone represent significant disorders with heterogeneous entities with varying pathophysiological basis like chronic inflammation, vasculitis, autoimmunity, and autoinflammation. Associations or complications of these diseases may remain obscure if their extensions are not explored specifically. Pediatric uveitis, non-uveitic inflammatory diseases, inflammatory bowel diseases, and autoinflammatory bone diseases are the important constituents of this cluster. The author concisely discusses these disorders in this review from pediatric rheumatological perspective. If untreated, these diseases may be organ-threatening. Outcomes are vastly different in undiagnosed patients and in timely diagnosed and treated patients. Lack of awareness and missed exploration of associated illnesses and complications may result in a missed diagnosis or inadequate symptomatic treatment. A multidisciplinary approach to diagnosis and treatment is desirable in these heterogeneous entities. Pediatricians must be aware of the immunological origin of organ-centered symptoms and signs. A proper understanding of molecular details of etiopathogenesis and significant advances in therapy have reduced the morbidity, disability, and mortality of such disorders.

Diagnosis of Immunoglobulin G4-related disease in a child with ligneous conjunctivitis: a novel mutation in plasminogen gene and plasminogen activator inhibitor-1 polymorphism

OBJECTIVES

Ligneous conjunctivitis (LC) is a chronic conjunctivitis characterized by recurrent, firm, fibrin-rich, woody pseudomembranes on the palpebral conjunctiva. It is an ultrarare autosomal recessive disease associated with congenital plasminogen (PLG) deficiency due to mutations in the PLG gene (6q26). Immunoglobulin G4-related disease (IgG4-RD) is an idiopathic, systemic fibroinflammatory disease characterized by elevated serum IgG4 concentration and tissue infiltration of IgG4-positive plasma cells leading to organ enlargement, fibrosis and damage.

CASE REPORT

A 7-year-old girl with LC was hospitalized for recurrent pancreatitis and diagnosed as IgG4-RD. PLG activity level was 15% (normal range 55-145%). Co-segregation analysis indicated that the patient was homozygous for the c. NG_016200.1(NM_000301.5):c.1465 T>C mutation in PLG gene. c. NG_016200.1(NM_000301.5):c.1465 T>C PLG variant was found to be heterozygous by NGS analysis in both parents. She also had plasminogen activator inhibitor - 1 (PAI-1) NG_013213.1(NM_000602.5):c.-816A>G (4G/4G) homozygous polymorphism and a heterozygote NG_001333.2 (NM_002769.5):c.292_293insC mutation in the serine protease 1 (PRSS-1) gene. However, heterozygous PRSS-1NG_001333.2 (NM_002769.5):c.292_293insC variant was found in the mother of the patient. All detected variants are currently considered as a variant of uncertain (or unknown) significance (VUS) according to the American College of Medical Genetics and Genomics (ACMG) classification. Oral steroid, oral azathioprine, topical fresh frozen plasma, topical heparin, topical steroid and topical cyclosporine were given. After 3 years of follow-up, IgG4-RD is under partial remission and no pseudomembranes.

CONCLUSION

She is the second case had both LC and IgG4-RD. We identified a NG_016200.1(NM_000301.5):c.1465 T>C novel homozygous mutation in PLG gene and a PAI-1 NG_016200.1(NM_000301.5):c.1465 T>C (4G/4G) homozygous polymorphism, which has been reported as a risk factor for thrombotic events.

Immunoglobulin G4-Related Disease, Lymphadenopathy, and Lymphoma

Lymphadenopathy occurring in patients with immunoglobulin G4 (IgG4)-related disease, termed IgG4-related lymphadenopathy, shows morphologic heterogeneity and overlap with other nonspecific causes of lymphadenopathy including infections, immune-related disorders, and neoplasms. This review describes the characteristic histopathologic features and diagnostic approach to IgG4-related disease and IgG4-related lymphadenopathy, with comparison to nonspecific causes of increased IgG4-positive plasma cells in lymph nodes, and with emphasis on distinction from IgG4-expressing lymphoproliferative disorders.

IgG4 related pericardium and lung disease in pediatric patient complicated with fatal massive hemoptysis: a case report and review of literature

BACKGROUND

IgG4-related disease (IgG4-RD) is a progressive and sometimes fatal disease that rarely affects pediatric age group. It may affect the orbits, lacrimal and salivary glands, pancreas, kidneys, peritoneum and other organs. Lung and pleura are not commonly reported in IgG4-RD. We here present a rare case of pediatric IgG4-RD with rare involvement of pericardium, pleura and lungs.

CASE PRESENTATION

A 13-year-old girl presented with intrathoracic IgG4-RD with pleuropericardial involvement. She showed initial improvement on prednisolone. Azathioprine and then mycophenolate failed to control relapses during steroid tapering. Her last relapse was treated by rituximab however, the patient developed acute fatal massive hemoptysis.

CONCLUSIONS

Pediatric IgG4-RD is a rare entity with pericardio-pulmonary affection as the rare of the rare. Usual treatment of prednisolone and steroid sparing agents should be used, with rituximab used as a rescue therapy, but fatal complications may occur.

Thoracic manifestations of IgG4-related disease

Immunoglobulin G4-related disease (IgG4-RD) is a recently described rare systemic fibroinflammatory disease with an estimated incidence of less than 1 in 100,000 persons per year. The disease can affect virtually any organ and is characterized by unifying histopathological findings. Recently, four subgroups of patients have been characterized: hepatobiliary, head and neck, Mikulicz syndrome and retroperitoneal fibrosis, who illustrate the mainly abdominal and ENT tropism of the disease. Yet, thoracic involvement is not uncommon. It can be detected in up to 30% of patients with systemic IgG4-RD and is the exclusive manifestation of the disease in about 10% of cases. Clinical symptoms are nonspecific and may include dyspnoea, cough or chest pain. Chest CT findings are heterogeneous and primarily include peribronchovascular thickening, nodules, ground-glass opacities and lymphadenopathy. There is no specific diagnostic test for IgG4-RD thoracic involvement, which may mimic malignancy or vasculitis. Therefore, a cautious approach is needed to make an accurate diagnosis: a search for extra-thoracic manifestations, elevated serum IgG4 levels, circulating levels of plasmablasts and pathologic evidence of disease is warranted. Although very suggestive, neither the presence of a polyclonal IgG4 lymphoplasmacytic infiltrate, storiform fibrosis or obliterative phlebitis are sufficient to confirm the histological diagnosis. Steroids are recommended as first-line therapy. Rituximab or disease-modifying antirheumatic drugs may be used in relapsed or rare cases of steroid-refractory disease. In this review, we summarize current knowledge regarding the pathophysiology, epidemiology, diagnostic modalities (clinical-biological-imaging-histopathology) and treatment of IgG4-RD thoracic involvement.

Report of Two Cases of Pediatric IgG4-Related Lymphadenopathy (IgG4-LAD): IgG4-Related Disease (IgG4-RD) or a Distinct Clinical Pathological Entity?

IgG4-related disease (IgG4-RD) is a recently discovered immune-mediated fibroinflammatory condition, uncommon in the pediatric population, that could involve multiple organs and induce cancer-like lesions and organ damage. Its main features are multiple injuries in different sites, a dense lymphoplasmacytic infiltrate rich in IgG4 plasma cells, storiform fibrosis, and often high serological concentrations of IgG4. Autoimmune pancreatitis is the most common manifestation, mainly in adults. Two cases of IgG4-RD in children with lymph node localization of disease are reported. Localized or systemic lymph node involvement is common, but lymph node enlargement as the first and only manifestation of IgG4-RD is unusual, and therefore, hard to differentiate from other diseases. IgG4-related lymphadenopathy (IgG4-LAD) is most likely a distinct disease, described as isolated lymphadenopathy, related to the presence of elevated numbers of IgG4-positive plasma cells. Both disorders are likely to be misdiagnosed in children because they are characterized by rare and polymorphic features. IgG4-RD and IgG4-LAD should be considered in the differential diagnosis of disorders characterized by lymphadenopathy of uncertain etiology.

How I approach: The workup and management of patients with progressive transformation of the germinal center

Progressive transformation of the germinal center (PTGC) is a common and underrecognized cause of pediatric lymphadenopathy. PTGC may be associated with numerous systemic medical conditions that require further workup and management, including malignancy, autoimmune conditions, lymphoproliferative conditions, immunodeficiency, and infection. Given the breadth and rarity of the associated conditions, workup should be tailored to the individual patient and occur in a tiered approach. Patients with PTGC require ongoing follow-up, given their long-term risk of malignancy and recurrent PTGC.

Overview of autoimmune liver disease: Prevalence, risk factors, and role of autoantibodies

Content available: Author Interview and Audio Recording.

[Immunoglobulin-G4-related disease]

After years of confusion about apparently distinct clinical disease symptoms, the term IgG4-related disease (IgG4-RD) has been coined in 2001, uniting these fibroinflammatory clinical entities with a tendency for tumorous enlargement and tissue fibrosis. Over the past two decades, experimental and clinical studies could make astounding progress in the understanding of this elusive disease. By now, we have a reasonable idea of the pathophysiological mechanisms, which opens up new avenues for therapeutic approaches. It seems like a dense lymphoplasmacytic cell infiltrate, consisting of B‑cells, IgG4⁺ plasma cells, follicular T‑helper cells, CD4⁺ cytotoxic T‑cells and M2 macrophages induces a smoldering inflammatory reaction with a fibrogenic cytokine milieu. This stimulates fibroblasts to secrete extracellular matrix components, leading to the histopathologically characteristic storiform fibrosis and obliterative phlebitis. Macroscopically, this reaction results in diffuse organ swelling and tumorous lesions. The macroscopic and histological differentiation from conditions mimicking IgG4-RD can be challenging. This is especially true for granulomatous diseases, such as antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). The situation is further complicated by the fact that ANCAs can be positive in IgG4-RD and, vice versa IgG4 antibodies can be elevated in numerous differential diagnoses, such as infections, AAV, sarcoidosis, and malignancies. This article provides an overview of the multifaceted clinical condition of IgG4-RD with respect to the pathophysiology, diagnostic steps and treatment. Furthermore, an overview of the differential diagnoses is discussed especially with respect to granulomatous diseases.

Imaging Findings of Pediatric Orbital Masses and Tumor Mimics

Pediatric orbital masses are not common but encompass a wide spectrum of benign and malignant entities that range from developmental anomalies to primary and secondary orbital malignancies and metastatic disease. Certain orbital tumors are unique to pediatric patients, such as retinoblastoma and neuroblastoma. Clinical symptoms and signs are often insufficient to differentiate between orbital lesions, and imaging is essential for narrowing the diagnostic considerations and determining the most appropriate management strategy. MRI is the primary imaging modality for evaluating orbital masses in children, with US and CT playing complementary roles. The authors review a spectrum of masses and tumor mimics that affect the pediatric globe and orbit. The shared and differentiating characteristics of pediatric orbital lesions are reviewed. Emphasis is placed on utilizing an orbital compartment-based approach to narrow the differential diagnosis. By using this organizational scheme, the authors describe intraocular processes (retinoblastoma, persistent fetal vasculature, and Coats disease), intraconal lesions (lymphatic malformation, schwannoma, optic nerve sheath meningioma, and optic pathway glioma), extraconal lesions (infantile hemangioma, rhabdomyosarcoma, idiopathic orbital inflammation, lymphoma, venous varix, plexiform neurofibroma, and pleomorphic adenoma of the lacrimal gland), and lesions involving the bony orbit (dermoid cyst, metastatic neuroblastoma, and Langerhans cell histiocytosis). The authors describe the basic management of each entity. Orbital infections and traumatic lesions are beyond the scope of this article. ^©RSNA, 2022.

Hepatic manifestations of systemic disease: an imaging-based review

The liver is responsible for many processes that maintain human metabolic homeostasis and can be affected by several pediatric systemic diseases. In this manuscript, we explore key pathological findings and imaging features across multiple modalities of a spectrum of congenital, metabolic and autoimmune disorders. Strengthening the radiologists' knowledge regarding potential hepatic manifestations of these systemic diseases will ultimately lead to improved care for pediatric patients.

IgG4-related cholecystitis misinterpreted as gallbladder cancer, a case report

Introduction

Immunoglobulin G4-related disease (IgG4-RD) is a new defined entity with features that factually have been overlapped with other diseases with distinctly diverse treatments and prognoses.

Case presentation

This report describes a 50-year-old woman who presented with abdominal pain from 3 months ago. The patient underwent open cholecystectomy with Roux-en-Y hepaticojejunostomy due to suspicious of malignancy. The histological examinations revealed acute on chronic cholecystitis with extensive fibrosis and many inflammatory cells infiltration composed of plasmacells and eosinophils without any evidence of malignancy. Pathological and immunohistochemical examination for IgG4 compatible with IgG4-RD. So, pathological assessment is essential for the diagnosis.

Conclusion

IgG4-RD in gastrointestinal tract frequently misinterpret as malignancy before surgery, and surgeon should notice this disease in the differential diagnosis in order to choose the treatment.

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IgG4-related disease is rare fibroinflammatory condition.

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Gastrointestinal IgG4-related disease is problematic to establish previous surgery.

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Malignancy is main differential diagnosis of IgG4-related cholecystitis.

Case Report: Atypical Manifestations Associated With FOXP3 Mutations. The “Fil Rouge” of Treg Between IPEX Features and Other Clinical Entities?

Introduction

The Forkhead box protein P3 (FOXP3) is a transcription factor central to the function of regulatory T cells (Treg). Mutations in the FOXP3 gene lead to a systemic disease called immune dysregulation, polyendocrinopathy, and enteropathy, an X-linked syndrome (IPEX) characterized by the triad of early-onset intractable diarrhea, type 1 diabetes, and eczema. An atypical presentation of IPEX has been reported.

Method

We report rare cases with equivocal clinical associations that included inflammatory, kidney, and hematologic involvements screened with massively parallel sequencing techniques.

Results

Two patients with hemizygous mutations of FOXP3 [c.779T&gt;A (p.L260Q)] and [c.1087A&gt;G (p.I363V)] presented clinical manifestations not included in typical cases of IPEX: one was a 16-year-old male patient with an initial clinical diagnosis of autoimmune lymphoproliferative syndrome (ALPS) and who developed proteinuria and decreased kidney function due to membranous nephropathy, an autoimmune renal condition characterized by glomerular sub-epithelial antibodies. The second patient was a 2-year-old child with bone marrow failure who developed the same glomerular lesions of membranous nephropathy and received a bone marrow transplantation. High levels of IgG4 in serum, bone marrow, and kidney led to the definition of IgG4-related kidney disease (IgG4 RKD) in this young boy. The circulating Treg levels were normal in the former case and very low in the second.

Conclusion

Two atypical associations of functional mutations of FOXP3 that include ALPS and IgG4 RKD are described. Membranous nephropathy leading to renal failure completed in both cases the clinical phenotypes that should be included in the clinical panorama of FOXP3 failure.

Cutting edge issues in juvenile sclerosing cholangitis

Sclerosing cholangitis (SC) is a rare chronic disorder characterised by inflammation and progressive obliterative fibrosis of the intrahepatic and/or extrahepatic bile ducts. Diagnosis is based on cholangiogram showing bile duct dilatation, narrowing and obliteration of the biliary tree, and histologically, on the presence of inflammatory bile duct damage leading to periductal fibrosis. In children the most common SC is associated with strong autoimmune features, overlapping with those of autoimmune hepatitis (AIH); this form is known as autoimmune sclerosing cholangitis, ASC. Conversely, primary SC (PSC), a condition in which the term "primary" indicates that aetiology and pathogenesis are unknown, is rare in paediatrics. Secondary SC (SSC) defines a cholangiopathy associated with an identifiable aetiology such as immunodeficiencies, infections or haematological disorders. ASC and PSC are strongly associated with inflammatory bowel disease (IBD). ASC responds biochemically well to immunosuppressive drugs and ursodeoxycholic acid (UDCA). Primary forms are exclusively managed with oral UDCA, while in the secondary forms the medical treatment depends on the underlying aetiology. Despite treatment, SC often progresses to biliary cirrhosis and end-stage liver disease requiring liver transplantation. The disease can recur after transplant. Better understanding of pathogenic mechanisms and better treatment modalities are needed to improve the prognosis of this invalidating hepatic disorder.

IgG4-Related Disease: Mimickers and Diagnostic Pitfalls

BACKGROUND

The tendency of IgG4-related disease (IgG4-RD) to form pseudotumors, as well as its multisystemic nature, makes it the perfect mimicker of many conditions. Moreover, some clinical, serological, radiological, or histological features of the disease might be shared with some mimickers.Recently, 4 clinical phenotypes have been identified, and patients grouped in each phenotype have distinctive demographic, clinical, and serological features and outcomes, and, as expected, for each phenotype, a set of differential diagnoses should be considered.

SUMMARY OF THE LITERATURE

The main differential diagnoses for the pancreato-hepato-biliary phenotype are pancreatic adenocarcinoma and cholangiocarcinoma. Other differential diagnoses include type 2 autoimmune pancreatitis and primary sclerosing cholangitis. In patients with retroperitoneal/aortic phenotype, inflammatory conditions such as idiopathic retroperitoneal fibrosis and large vessel vasculitides should be ruled out, and most of the time, a biopsy will be needed to exclude malignancies. In head and neck limited phenotype, autoimmune conditions (eg, granulomatosis with polyangiitis, Graves orbitopathy, sarcoidosis), malignancies, and histiocytosis should be ruled out, whereas the main differential diagnoses of the Mikulicz/systemic phenotype are Sjögren syndrome, granulomatosis with polyangiitis, and multicentric Castleman disease.

CONCLUSIONS

Approaching a patient with probable IgG4-RD through a clinical phenotype framework will ease the diagnostic algorithm and facilitate the prompt recognition of the disease. There are certain clinical, serological, radiological, and histological features in each clinical phenotype that, if present, increase the likelihood that a patient may have IgG4-RD instead of the mimicker condition. Those clues that point toward IgG4-RD diagnosis should be actively sought in the workup of patients.

Update on classification, diagnosis, and management of immunoglobulin G4-related disease

Immunoglobulin G4-related disease (IgG4-RD) is a newly recognized chronic fibro-inflammatory autoimmune disease, and its recognition has been constantly increasing worldwide over the last few years. A correct and timely recognition, as well as appropriate intervention, is crucial for the treatment of IgG4-RD. For certain subtypes of IgG4-RD, organ-specific criteria are formulated to make the diagnosis more accurate. New biomarkers have emerged in the recent years to aid the disease diagnosis, its prognosis prediction, as well as therapy response monitoring. Although recurrence is very common in IgG4-RD, glucocorticoid is still the first-line treatment for the majority of patients. The factors that affect the likelihood of disease relapse are multifaceted. The selection strategy of various steroid-sparing agents is still being explored. Besides, when patients have special sites involvement leading to severe clinical conditions, surgical operation or interventional therapy should also be considered. An update on classification, diagnosis, and management of IgG4-RD is provided in the current study to fully elucidate the recommended clinical practice of this mysterious disease.

Ophthalmic involvement disparities in clinical characteristics of IgG4-related disease: a retrospective study of 573 patients

Purpose

To investigate the clinical manifestations of orbital involvement in a large cohort of Chinese patients with IgG4-related disease (IgG4-RD).

Methods

A total of 573 patients with IgG4-related disease were included. We described and compared the demographic, clinical, laboratory and histopathologic findings from 314 patients with IgG4-related ophthalmic disease (IgG4-ROD) and 259 with extra-ophthalmic IgG4-RD.

Results

Male predominance was found significant in extra-ophthalmic IgG4-RD only. Patients with IgG4-ROD showed younger age at diagnosis and longer duration from onset till diagnosis. In patients with extra-ophthalmic IgG4-RD, the most commonly involved extra-ophthalmic organ was pancreas; while in IgG4-ROD patients, salivary gland was most frequently affected. Multivariate analysis exhibited IgG4-ROD was associated with allergy history, higher serum IgG4/IgG ratio, multiple organs involvement and sialoadenitis. Orbital images were reviewed in 173 (55.1%) IgG4-ROD patients. Fifty-one (29.5%) patients had multiple lesions. Lacrimal gland involvement was detected in 151 (87.3%) patients, followed by extraocular muscles (40, 23.1%), other orbital soft tissue (40, 23.1%) and trigeminal nerve (8, 4.6%). Biopsy was performed from various organs in 390 cases. A dense lymphoplasmacytic infiltration and fibrosis were the main feature in orbital specimens. Storiform fibrosis and obliterative phlebitis were absent in lacrimal gland.

Conclusions

Lacrimal gland involvement was the most common orbital manifestation of IgG4-ROD. Patients with IgG4-ROD showed different characteristic in demographic, clinical, laboratory findings compared to patients with extra-ophthalmic IgG4-RD. These features might indicate potential differences in the pathogenesis of these two subgroups of IgG4-RD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12886-021-02210-z.

IgG4-related chronic sclerosing sialadenitis in a child with recurrent parotitis: a case report

Background

IgG4-related disease (IgG4-RD) includes a group of immune-mediated diseases histologically characterized by lymphoplasmacytic infiltrate with a prevalence of IgG4-positive plasma cells, storiform fibrosis and obliterative phlebitis. Autoimmune pancreatitis, sialadenitis, dacryoadenitis and retroperitoneal fibrosis are the most frequent manifestations. IgG4-related sialadenitis usually affects submandibular glands and is very rare in children.

Here we report the case of IgG4-related sialadenitis in a six-year-old patient previously diagnosed as juvenile recurrent parotitis.

Case presentation

A six-year-old patient was referred to our Centre for left parotid swelling of 4 × 3 cm, that was tender, soft in consistency, with overlying red and warm skin. His general condition was good but he was subfebrile; general examination revealed mild enlargement of left cervical lymph nodes. In the last 2 years he had had five episodes of parotitis, diagnosed by another pediatric Center as juvenile recurrent parotitis.

On ultrasound examination the left parotid gland appeared enlarged, inhomogeneous, with a colliquative intraparotid lymph node and no evidence of sialolithiasis. Laboratory tests showed an increase of white blood cells and anti-VCA IgM and IgG positivity, with anti-EBNA e anti-EA I negativity.

The patient was initially treated with oral antibiotics, but after 10 days the parotid became fluctuating, requiring surgical biopsy and drainage. Postoperative course was regular, with complete remission under oral antibiotic and steroid therapy. Microbiological tests, including cultures for aerobic and anaerobic bacteria, mycobacteria and Bartonella, were negative.

Surprisingly, histology showed marked fibrosis and histiocytic and lymphoplasmacellular infiltrate with polyclonal plasma cells mostly expressing IgG4 immunoglobulins. Thus, the diagnosis of IgG4 related chronic sialadenitis in recurrent parotitis and recent EBV infection was made.

Conclusions

IgG4-related sialadenitis is very unusual in children. Histology plays a key role in diagnosis, considering that up to 30% of patients have normal serum IgG4 levels, as shown in our case.

The lack of previous histological data makes it impossible to attribute our patient’s previous episodes of parotitis to IgG4-RD, though it is a very consistent possibility.

Clinical Perspectives on IgG4-Related Disease and Its Classification

Immunoglobulin G4-related disease (IgG4-RD) is a systemic immune-mediated fibroinflammatory disease. Since its discovery nearly two decades ago, our understanding of its pathophysiology and clinical manifestations has grown substantially. Early diagnosis and treatment of this elusive disease can prevent substantial organ damage from end-stage fibrosis, emphasizing the need for prompt recognition and accurate characterization of IgG4-RD. The classification criteria endorsed by the American College of Rheumatology and the European Alliance of Associations for Rheumatology in 2019 provide a framework for establishing the diagnosis in the clinical setting. This process involves recognizing the typical manifestations of the disease and incorporating clinical, radiological, serological, and histopathological information as well as excluding disease mimickers. Glucocorticoids and rituximab are effective at inducing remission in IgG4-RD in most patients, but the optimal approach to long-term management of IgG4-RD remains an area of active clinical research. Expected final online publication date for the Annual Review of Medicine, Volume 73 is January 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Clinicopathologic Characterization of IgG4-Rich Pediatric Head and Neck Lesions

CONTEXT.—

Immunoglobulin G4 (IgG4)-related disease is rare but well characterized in adults; however, the clinical and histologic manifestations in children may differ.

OBJECTIVE.—

To review the clinical and histologic features of IgG4-rich head and neck lesions in a pediatric population.

DESIGN.—

Retrospective search for cases with IgG4 immunohistochemical staining performed at our institution from 2011 to 2019. Review of clinical courses, serology profiles, histologic patterns, and immunohistochemical staining patterns.

RESULTS.—

Four pediatric IgG4-rich lesions were identified and showed distinct histologic patterns from adult IgG4-related disease, including absence of pathognomonic findings associated with the latter. One case showed intralesional immunoglobulin light-chain restriction. Clinical review showed serum IgG4 elevation in 2 of 4 cases, presence of additional autoantibody positivity, and a generally benign/treatment-responsive clinical course.

CONCLUSIONS.—

Pediatric IgG4-related disease shows distinct clinical, serologic, and histologic features from its adult counterpart. Pediatric IgG4-related disease involving the orbit has unique clinical characteristics, including frequently normal serum IgG4 levels and female predominance. Awareness and evaluation for these features may improve diagnosis and treatment.

IgG4-related disease of the orbit in an infant

IgG4-related disease is a chronic fibroinflammatory disorder that is becoming increasingly recognized in the pediatric population. The orbit is one of the most commonly affected sites. We present the youngest case of IgG4-related ophthalmic disease in the literature, with an immunodeficiency phenotype associated with a homozygous IRAK-4 variant gene. We also review the clinical and histological features in children with IgG4-related ophthalmic disease. In addition to the young age of presentation, the case is unique for absence of lacrimal gland involvement, dural enhancement on magnetic resonance imaging, and an association with an IRAK-4 deficiency phenotype. Management required a multidisciplinary approach, with judicious use of immunosuppression. IgG4-related ophthalmic disease should be considered as a differential diagnosis in infants and children presenting with an orbital mass. Further, a particularly young age of onset may indicate an overarching immune dysregulation syndrome.

A Case of Tracheal Stenosis as an Isolated Form of Immunoproliferative Hyper-IgG4 Disease in a 17-Year-Old Girl

Immunoglobulin G4-related disease (IgG4-RD) is a lymphoproliferative disease which is described almost exclusively in adults. There are only a few pediatric patients who have been observed with this disorder. Here, we describe a rare case of IgG4-RD in a 17-year-old girl with a single manifestation—tracheal stenosis without previous intubation or other inciting event. She had mixed dyspnea and noisy and weakened breathing. Immunoproliferative hyper-IgG4 disease was diagnosed, based on elevated serum IgG4 and histological findings. Until now we have chosen to treat the girl only with corticosteroids with a good response so far. The general condition as well as the respiratory function are regularly monitored. The tracheal involvement of IgG4-RD is uncommon. Nonetheless, it is a manifestation that should be included in the differential diagnosis of tracheal stenosis.

Reactive Lymphadenopathies

Lymphadenitis in the pediatric population frequently is benign and self-limited, often caused by infections. In children with refractory symptoms, lymph node biopsy may be indicated to rule out malignancy or obtain material for culture. Acute bacterial infections typically show a suppurative pattern of necrosis with abscess formation. Viral infections are associated with nonspecific follicular and/or paracortical hyperplasia. Granulomatous inflammation is associated with bacterial, mycobacterial, and fungal infections. Toxoplasma lymphadenitis displays follicular hyperplasia, monocytoid B-cell hyperplasia, and clusters of epithelioid histiocytes. Autoimmune and noninfectious inflammatory disorders are included in differential diagnosis of lymphadenitis. Infectious mononucleosis and Kikuchi-Fujimoto lymphadenitis may mimic Hodgkin and non-Hodgkin lymphomas.

[IgG4-related disease]

BACKGROUND

The IgG4-related systemic disease as well as the homonymous variant IgG4-related orbital disease were first described less than 15 years ago. The mostly subacute clinical symptoms can be multifarious and the classical case is characterized by an orbital inflammatory condition with a bilateral enlargement of the lacrimal glands; however, any other orbital tissue with the exception of the eyeball can be affected by the lymphocytic inflammatory infiltration.

MATERIAL AND METHODS

Based on the current literature the clinical picture, epidemiology, pathogenesis and treatment options are described. A focus is on the differential diagnostic demarcation from other inflammatory processes of the orbit.

CONCLUSION

The IgG4-related orbital disease is an important differential diagnosis of inflammatory diseases of the orbit. The condition can exhibit considerable clinical and imaging similarity to idiopathic inflammation of the orbit, to the specific inflammations seen in systemic diseases, to Graves' orbitopathy and to lymphoproliferative diseases and lymphoma. After histopathologic confirmation the interdisciplinary clarification and treatment consensus are indispensable.

Differences in clinical characteristics of IgG4-related disease across age groups: a prospective study of 737 patients

OBJECTIVE

The aim of this study was to compare the clinical characteristics of IgG4-related disease (IgG4-RD) among different age groups.

METHODS

We conducted a prospective study of 737 patients who were newly diagnosed with IgG4-RD and compared detailed demographic features, organ involvements, laboratory tests, treatments and outcomes across age groups. The patients were divided into five groups according to their age at diagnosis: ≤39, 40-49, 50-59, 60-69 and ≥70 years. The clinical characteristics of paediatric patients were also described.

RESULTS

Sex ratio, disease duration, allergy history and clinical symptoms were significantly different across age groups. Besides, the proportions of superficial organ involvement (lacrimal gland and sinus) decreased with age, while the proportions of internal organ involvement (pancreas, biliary tract, retroperitoneal tissue, lung and prostate) increased with age, which was more prominent in male patients. Mikulicz's disease was the most common manifestation (70%) in paediatric IgG4-RD patients. Multiple Cox analysis identified that age ≤56 years at diagnosis was an independent risk factor of relapse.

CONCLUSION

We revealed the impact of age on clinical characteristics of IgG4-RD, which indicated that different management might be required among different age groups.

Conjunctival Infiltration in a Child as a Rare Manifestation of IgG4-Related Disease

PURPOSE

Ocular manifestations of immunoglobulin G4 (IgG4)-related disease are common in children although remain ill-defined because of the disease's rarity. We describe a pediatric case of IgG4-related orbital disease (IgG4-ROD) who presented with persistent conjunctival infiltration before developing lacrimal gland enlargement 3 years later.

METHODS

This was a case report.

RESULTS

An 8-year-old girl developed forniceal salmon-patch-like conjunctival lesions in her left eye that were refractory to topical corticosteroids. Investigations, including an orbital MRI and 2 conjunctival biopsies, were negative for lymphoma. She was treated with topical corticosteroids and then nonsteroidal antiinflammatory drops. The lesions decreased mildly, and no new lesion emerged. After 3 years, the patient developed a ptosis, new salmon-patch conjunctival lesions, and papillae. Vision deteriorated to 20/80 because of severe punctate epithelial erosions in the left eye, and the Schirmer test was significantly reduced. A repeat MRI revealed an enlarged left lacrimal gland. A biopsy was performed and was compatible with IgG4-ROD. An elevated IgG4 level of 4.61 g/L was also found. The patient was successfully treated with oral prednisone but flared on tapering the dosage. Rituximab was therefore initiated with excellent clinical response, and prednisone was discontinued. Vision returned to 20/20 after aggressive lubrification, punctal plugs, and autologous serum eye drops. Tear function came back to normal, and local treatments were stopped.

CONCLUSIONS

This case describes a pediatric case of IgG4-ROD presenting initially with conjunctival follicular reaction, later developing lacrimal gland involvement. Therefore, it is important to consider IgG4-ROD in chronic atypical follicular conjunctival lesions in children, even in the absence of orbital disease.

IgG4-related disease in pediatric patients: a single-center experience

OBJECTIVE

Immunoglobulin G4-related disease (IgG4-RD) is a systemic, immune-mediated, and fibroinflammatory disease that can affect almost any organ system. We aimed to present our single-center experience of pediatric patients with IgG4-RD, a rare disease in children.

METHODS

Pediatric patients diagnosed with IgG4-RD at the Hacettepe University between June 2014 and September 2020 were evaluated retrospectively. Patients with definite, probable, or possible diagnosis of IgG4-RD were included.

RESULTS

A total of eight patients with a median age of 13.4 (IQR 9.5-15.0) years were included in the study. Clinical presentations were IgG4-related ophthalmic disease in six patients, IgG4-related lymphadenopathy in one patient, and IgG4-related sialadenitis and lymphadenopathy of several lymph nodes accompanied by pancreatitis, ulcerative colitis, and pulmonary manifestations in one patient. Elevated serum IgG4 was detected in three of eight patients (37.5%). The main histopathological feature was fibrosis and lymphoplasmacytic infiltrates. Corticosteroids were used as first-line treatment in almost all patients with or without steroid-sparing agents. Azathioprine, methotrexate and rituximab were used as steroid-sparing agents. Relapse occurred in two of seven patients. Radiotherapy was used as the last resort in one patient with severe orbital disease.

CONCLUSION

IgG4 RD mainly presents with orbital manifestations in pediatric population but has wide phenotypic clinical variability. Although rare, early recognition and treatment are essential for a better outcome in these patients.

Pediatric renal pseudotumour

We present a case of 6-year-old female with history of respiratory distress who went into respiratory failure requiring intubation. Patient was subsequently found to be in hypertensive crisis with hyponatremic hypochloremic metabolic acidosis and acute kidney injury. Renal ultrasound was performed to find the cause of hypertension. The ultrasound study demonstrated lobulated isoechoic to hyper echoic mass-like lesion in the middle and lower pole of the right kidney with increased vascularity on Color Doppler examination. The renal mass was finally diagnosed as a pseudotumour, representing hypertrophied portion of the spared normal renal parenchyma in otherwise atrophic right kidney. Diagnosis was made using a combination of US, MRI, DMSA and CT angiography thus avoiding unnecessary surgical intervention.

FDG-Avid Pulmonary Nodules and Tracheobronchial Mural Inflammation in IgG4-Related Disease

ABSTRACT

We report the case of a 9-year-old girl who presented with acute fevers, cough, and epistaxis with nasal swelling, and found to have a nasal mass. On 18F-FDG PET/CT, she was found to have marked nodal and pulmonary parenchymal disease with diffuse and symmetrical mural FDG uptake within the trachea and bronchial tree. The differential diagnosis was broad, and she was diagnosed with IgG4-RD (IgG4-related disease) and improved on appropriate treatment. To our knowledge, there are only 2 other pediatric cases of IgG4-related pulmonary disease in the literature, and our case serves as a unique constellation of intrapulmonary IgG4-RD imaging findings.