Recommendations for the nomenclature of IgG4-related disease and its individual organ system manifestations

CT Chest findings in IgG4-related disease

PURPOSE

To investigate the multi-slice spiral Computed Tomography(MSCT) findings of chest involvement in IgG4-related diseases and to improve doctors' understanding of this disease.

MATERIALS AND METHODS

We retrospectively analyzed the clinical and imaging data of 67 patients with clinically confirmed or suspected IgG4-related diseases.

RESULTS

Sixty patients (89.60%) had abnormal chest CT findings. Among them, 47 patients (70.10%) had enlarged mediastinal lymph nodes. Thickening of the tracheal and tracheobronchial perivascular walls was observed in 35 patients (52.20%). Nodules were observed in 29 patients (43.30%). Patches or ground-glass opacities were observed in 15 cases (22.40%); bilateral enlarged axillary lymph nodes, 9 (13.40%); bilateral enlarged hilar lymph nodes, 3 (4.50%); and, interstitial changes, 3 (11.90%). Pleural and pericardial effusion occurred in five cases (7.46%, two bilateral and three unilateral) and three cases (4.50%), respectively. Seven (10.45%) patients showed no obvious abnormalities. The abnormally elevated IgG4 level (>135 mg/dL) was positively correlated with thickening of the tracheal and tracheobronchial walls (r = 0.328, p = 0.007) and enlargement of mediastinal lymph nodes (r = -0.252, p = 0.039), and the logistic regression model 1 showed that the incidence of lung as the first symptom was higher in patients with bilateral enlarged hilar lymph nodes on chest images.

CONCLUSION

Chest CT is of great significance for the diagnosis and follow-up of IgG4-RLD. Chest CT scans should be suggested to be performed when ocular symptoms, bilateral enlarged hilar lymph nodes, pancreatitis, pituitary adenitis, Takayasu arteritis, or abnormally elevated IgG4 levels (>135 mg/dL) are present, and IgG4-RLD should be considered.

CT surveillance for type 1 autoimmune pancreatitis: cumulative radiation dose and diagnostic performance for disease relapse

OBJECTIVES

Long-term follow-up is essential for type 1 autoimmune pancreatitis (AIP) patients due to high relapse rates. The cumulative radiation dose from repeated CT scans during follow-up should not be ignored. We aim to investigate the cumulative radiation dose in AIP patients undergoing CT surveillance and the diagnostic performance of CT in detecting disease relapse. The diagnostic performance of MRI from a secondary cohort during the same period was also investigated.

METHODS

This retrospective single-institutional study included 247 type 1 AIP patients with one or more follow-up CT scans, and 120 patients with MR follow-ups. Four metrics were utilized to report the radiation dose, including the volume computed tomography dose index, the dose length product, size-specific dose estimate and effective dose. The diagnostic performance for AIP relapse was assessed, taking the final clinical diagnosis in retrospect as the reference standard.

RESULTS

With a median 2.3-year follow-up period, AIP patients followed up with CT exhibited a median cumulative radiation dose of 37.5 mSv. 11.3% of patients have accumulated doses exceeding 100 mSv. For the 169 patients followed over a year, 30.8% sustained an average annual radiation dose surpassing 20 mSv. The sensitivity/specificity/accuracy of CT for detecting abdominal organ relapse was 64.1%/99.6%/97.0%. For AIP patients followed up with MRI, the sensitivity for detecting disease relapse was 90.5%.

CONCLUSION

Considering the accumulation of radiation dose in AIP patients and the insufficient sensitivity in detecting disease relapse with CT, safer and more sensitive imaging follow-up strategies should be explored.

KEY POINTS

Question CT, as the primary imaging modality for autoimmune pancreatitis (AIP) follow-up, raises concerns regarding radiation exposure and lacks reported diagnostic performance in detecting AIP relapse. Findings CT in AIP follow-up causes significant cumulative radiation exposure and exhibits insufficient sensitivity in relapse detection. Clinical relevance Type 1 AIP necessitates long-term imaging follow-up, yet current guidelines lack consensus regarding the prioritization of CT or MRI for such follow-up. CT is widely used but has radiation concerns and limited sensitivity, calling for safer, efficient strategies.

IgG4‑related disease with endobronchial nodules: A case report and literature review

The present case report describes the case of a rare presentation of IgG4-related lung disease (IgG4-RLD) with endobronchial nodules and systemic involvement. An 84-year-old male presented with unexplained weight loss and enlarged submandibular lymph nodes. Diagnostic examinations revealed elevated serum IgG4 levels, along with findings of endobronchial nodules during bronchoscopy. Biopsies of endobronchial nodules revealed benign bronchial mucosa with fibrosis and inflammatory infiltration; however, he was not diagnosed with IgG4-RLD. A histological examination of the left salivary gland and submandibular lymph nodes confirmed the diagnosis of IgG4-related disease, revealing storiform fibrosis and abundant IgG4-positive plasma cells. The patient was treated with prednisolone, resulting in a reduction in submandibular swelling and decreased serum IgG4 levels. This case emphasizes the importance of considering IgG4-RLD as a potential diagnosis in patients presenting with endobronchial nodules and systemic disease. Accurate sampling methods, such as surgical lung biopsy or transbronchial cryobiopsies, are crucial for definitive diagnosis. Increased awareness among physicians can lead to timely recognition and appropriate management of this rare condition.

IgG4-related ophthalmic disease presenting as posterior scleritis in a pediatric patient

PURPOSE

To report IgG4-related ophthalmic disease (IgG4-ROD) presenting as posterior scleritis in a pediatric patient.

OBSERVATIONS

A 7-year-old girl presented with proptosis, painful eyelid swelling, and restricted extraocular movements (EOM) of her left eye (OS). Visual acuity (VA) was 20/20 in right eye (OD) and counting fingers (CF) at 1 foot in OS. Slit lamp examination revealed 2 + anterior chamber (AC) cells, optic disc edema (ODE) with elevated appearance of macula in OS. Optical coherence tomography (OCT) showed significant subretinal fluid (SRF) in macula, B-scan ultrasound (US) demonstrated T-sign in OS. Orbital MRI was also consistent with posterior scleritis and periorbital inflammation. Extensive systemic work-up was unremarkable. Thus, the patient was started on intravenous methylprednisolone (IVMP) 30 mg/kg/day for 3 days, along with topical therapy in OS, which led to an improvement of proptosis, EOM restriction, AC cells, as well as ODE and SRF in macula in OS. Fluorescein angiography (FA) showed leakage from optic disc in OS. The patient was then switched to oral prednisone with slow tapering and started on methotrexate (MTX). Given the recurrence of proptosis and painful eyelid swelling on systemic steroid tapering, serum IgG4 levels were ordered and found to be elevated at 149.9 mg/dL (range, 1-99). Therefore, the patient was diagnosed as 'possible' IgG4-ROD (based on diagnostic criteria) and started on infliximab (7.5 mg/kg) and IVMP monthly infusions with continuation of MTX 20 mg weekly and slower tapering of oral prednisone, which led to resolution of clinical findings, improvement of VA to 20/20 in OS.

CONCLUSION AND IMPORTANCE

Posterior scleritis may be the initial presentation of IgG4-ROD in children. Refractory course is not uncommon. Biologics are effective in the long-term control of inflammation.

Histopathological Markers of Immunoglobulin G4-related Disease: Analyzing Diagnostic Patterns and Immunohistochemical Findings

Introduction: Immunoglobulin G4 (IgG4) related disease is a localized or multisystem chronic inflammatory disease with characteristic pathological features. Several consensus criteria are available to aid in the diagnosis and its management. These criteria are highly specific, owing to their dependency on major histopathological criteria and laboratory investigations to diagnose IgG4-related diseases (IgG4-RD). We evaluated the lesions diagnosed as IgG4-RDs with histopathological scoring criteria based on histopathology, immunohistochemistry, and serology in the screening of IgG4-RDs. Materials and methods: The lesions diagnosed as IgG4-RD during the study period were evaluated using the histopathological scoring criteria which include storiform fibrosis, obliterative phlebitis, plasmacytic infiltrates, and lymphoid follicles. Immunohistochemistry with IgG4 was performed on all these lesions. Results: There were twelve patients with IgG4-RD involving the retroperitoneum, pancreas, lymph node, and nasal sinuses. Lesions involving the retroperitoneum showed all the characteristic histopathological findings of IgG4-RD. Storiform fibrosis and obliterative vasculitis were seen in 67% and 58% of the lesions respectively. Two patients (17%) lacked both storiform fibrosis and obliterative phlebitis. Additionally, lymphoid follicles were present in 58%, perineural infiltration in 33%, and tissue eosinophilia in 58% of individuals. Two patients with eosinophilic angiocentric fibrosis and a single patient with IgG4-RD associated with retroperitoneal mucinous cystadenoma were identified. Conclusion: IgG4-RD is a group of rare diseases that needs a multidisciplinary team approach for diagnosis. In our study, we report a rare association of IgG4-RD and retroperitoneal mucinous cystadenoma as well as rare lesions of IgG4-related eosinophilic angiocentric fibrosis. Clinicopathological and radiological correlation is crucial in the accurate diagnosis of IgG4-RD and to avoid overdiagnosis.

Neutrophil extracellular DNA traps activate the TLR9 signaling pathway of pancreatic ductal epithelial cells in patients with type 2 autoimmune pancreatitis

The presence of neutrophil infiltration around the pancreatic ducts has been found to be associated with type 2 autoimmune pancreatitis (AIP). However, the functional role and clinical significance of neutrophil migration in the progression of pancreatitis is not fully understood. Here, we found that neutrophil extracellular traps (NETs) are abundant around the pancreatic duct in patients with type 2 AIP. We also observed an increased expression of toll-like receptor 9 (TLR9) in pancreatic ductal epithelial cells (HPDEC) in type 2 AIP patients compared to other pancreatic diseases. TLR9 acts as the DNA component of NETs (NET-DNA) receptor in HPDEC, which senses extracellular DNA and subsequently activates the NF-κB pathway to promote neutrophil recruitment and induce NET formation. In addition, our results indicated that the hydroxychloroquine (HCQ), acting as a TLR9 antagonist, could effectively inhibit the activation of inflammatory pathways, reduce neutrophil migration and block the positive feedback loop. The intervention positions HCQ acts as a potential target drug for the clinical treatment of type 2 AIP.

A case of massive hemoptysis caused by immunoglobulin G4-related respiratory disease in adults: case report and review of literature

Immunoglobulin G4-related disease (IgG4-RD) is an immune-mediated chronic fibro-inflammatory condition, that can involve multiple systems. Immunoglobulin G4-related respiratory disease (IgG4-RRD) is relatively rare, with non-specific clinical symptoms. Hemoptysis is a rare clinical symptom of IgG4-RRD, and cases of massive hemoptysis in adults have not been reported. We present here a rare case of massive hemoptysis caused by IgG4-RRD in adults and review relevant literature. An 84-year-old female presented with recurrent cough and blood-streaked sputum, progressing to massive hemoptysis. Her chest CT showed patchy lesions in the lungs, initially misdiagnosed as a tumor. Ultimately, a biopsy confirmed the diagnosis of IgG4-RRD. The patient was treated with prednisone combined with leflunomide, which controlled her condition and maintained remission. However, after 13 months without hemoptysis, she experienced intermittent hemoptysis followed by a massive episode. Increasing the prednisone dose and continuing leflunomide treatment controlled the condition once again, with no recurrence in the subsequent year of follow-up. In patients with IgG4-RRD, particularly those with hemoptysis, it is essential to remain vigilant for massive hemoptysis. Similarly, in patients with lung patch lesions and no evidence of a tumor on biopsy, IgG4-RRD should not be overlooked. Early diagnosis and timely treatment can improve the patient's clinical prognosis.

IgG4-related disease for the hematologist

Immunoglobulin G4-related disease (IgG4-RD) is an immune-mediated disease with many important manifestations in hematopoietic and lymphoid tissue. IgG4 is the least naturally abundant IgG subclass, and the hallmark feature of IgG4-RD is markedly increased IgG4-positive plasma cells (with an IgG4 to IgG ratio >40%) in affected tissue, along with elevated polyclonal serum IgG and IgG4 in most patients. Histological diagnosis is essential, and other key features include storiform fibrosis, lymphoplasmacytic infiltrate, tissue eosinophilia, and obliterative phlebitis. The disease can present with predominantly proliferative features, such as swollen lacrimal and salivary glands, orbital pseudotumor, autoimmune pancreatitis, polyclonal hypergammaglobulinemia (PHGG), eosinophilia, and tubulointerstitial nephritis of the kidneys, or predominantly fibrotic disease, including mediastinal and retroperitoneal fibrosis, sclerosing mesenteritis, and hypertrophic pachymeningitis. This review focuses on 4 key hematological manifestations: PHGG, IgG4-positive plasma cell enriched lymphadenopathy (LAD), eosinophilia, and retroperitoneal fibrosis (RPF). These features are found in 70%, 60%, 40%, and 25% of IgG4-RD patients, respectively, but can also represent key hematological "mimickers" of IgG4-RD, including Castleman disease (PHGG, LAD), eosinophilic vasculitis (eosinophilia, PHGG, LAD), hypereosinophilic syndromes (eosinophilia, LAD, PHGG), and histiocyte disorders (PHGG, LAD, RPF). An organized approach to these 4 manifestations, and how to distinguish IgG4-RD from its mimickers, is explained. Proliferative manifestations typically respond very well to treatment corticosteroids, rituximab, and other immunosuppressives, whereas chronic fibrotic disease may not be reversible with current treatment modalities.

Immunoglobulin G4-related spinal pachymeningitis: A case report

BACKGROUND

Immunoglobulin G4-related disease (IgG4-RD) is a complex immune-mediated condition that causes fibrotic inflammation in several organs. A significant clinical feature of IgG4-RD is hypertrophic pachymeningitis, which manifests as inflammation of the dura mater in intracranial or spinal regions. Although IgG4-RD can affect multiple areas, the spine is a relatively rare site compared to the more frequent involvement of intracranial structures.

CASE SUMMARY

A 70-year-old male presented to our hospital with a two-day history of fever, altered mental status, and generalized weakness. The initial brain magnetic resonance imaging (MRI) revealed multiple small infarcts across various cerebral regions. On the second day after admission, a physical examination revealed motor weakness in both lower extremities and diminished sensation in the right lower extremity. Electromyographic evaluation revealed findings consistent with acute motor sensory neuropathy. Despite initial management with intravenous immunoglobulin for presumed Guillain-Barré syndrome, the patient exhibited progressive worsening of motor deficits. On the 45th day of hospitalization, an enhanced MRI of the entire spine, focusing specifically on the thoracic 9 to lumbar 1 vertebral level, raised the suspicion of IgG4-related spinal pachymeningitis. Subsequently, the patient was administered oral prednisolone and participated in a comprehensive rehabilitation program that included gait training and lower extremity strengthening exercises.

CONCLUSION

IgG4-related spinal pachymeningitis, diagnosed on MRI, was treated with corticosteroids and a structured rehabilitation regimen, leading to significant improvement.

A Review of IgG4-related Sclerosing Cholangitis (IgG4-SC)

IgG4-related sclerosing cholangitis (IgG4-SC) is a unique, steroid-responsive, fibroinflammatory condition that is more commonly found in older men and is strongly associated with autoimmune pancreatitis (AIP). It may pose a diagnostic challenge at times due to closely mimicking hepatobiliary diseases such as primary sclerosing cholangitis (PSC), secondary sclerosing cholangitis (SSC), and cholangiocarcinoma. IgG4-SC has an excellent prognosis when promptly diagnosed and treated with steroids. Literature search strategy: The authors searched PubMed and Google Scholar, for articles with the search terms "autoimmune cholangiopathy" and "IgG4 cholangiopathy."

Evaluation of the specificity of trigeminal nerve enlargement in the diagnosis of IgG4-related ophthalmic disease

PURPOSE

Enlargement of the trigeminal nerve is observed in 20-53% of patients with IgG4-related ophthalmic disease (IgG4-ROD) and is known to be a useful finding for the diagnosis of IgG4-ROD. On the other hand, enlargement of the trigeminal nerve has also been found at a certain frequency in orbital lymphoproliferative diseases other than IgG4-ROD. Therefore, we here re-evaluated the specificity of trigeminal nerve enlargement in the diagnosis of IgG4-ROD.

STUDY DESIGN

Retrospective, comparative study.

METHODS

A total of 149 consecutive cases of IgG4-ROD diagnosed at the Department of Ophthalmology, Tokyo Medical University Hospital were studied. As controls, 218 cases of orbital lymphoma, 13 cases of reactive lymphoid hyperplasia (RLH), and 117 cases of benign orbital tumors other than lymphoproliferative diseases were included. Enlargement of the trigeminal nerve (infraorbital or supraorbital nerve) in IgG4-ROD and all the control cases was evaluated on MRI or CT coronal images.

RESULTS

Enlargement of the trigeminal nerve was observed in 35 of the 149 cases (23.5%) of IgG4-ROD and in 7 of the 218 cases (3.2%) of lymphoma, with a significantly highly frequency in IgG4-ROD (P < .0001). No cases of trigeminal nerve enlargement were observed in the cases of RLH or benign orbital tumors. The sensitivity and the specificity of trigeminal nerve enlargement in the diagnosis of IgG4-ROD were 23.5% and 96.8%, respectively. Additionally, enlargement of the trigeminal nerve was significantly more common in men than in women (P < .028).

CONCLUSIONS

The present study indicates that trigeminal nerve enlargement is a characteristic imaging finding and has diagnostic value for IgG4-ROD.

Spinal cord compression by cystic IgG4-related spinal pachymeningitis mimicking neurocysticercosis: a case report

BACKGROUND

To report a case of IgG4-related pachymeningitis presenting with cystic lesions mimicking neurocysticercosis.

CASE PRESENTATION

A 40-year-old female patient with tetraparesis, dysphagia and dysphonia was evaluated with clinical examination, magnetic resonance imaging, and meningeal biopsy. Magnetic resonance imaging (MRI) revealed diffuse pachymeningeal enhancement involving the cranial, cervical, thoracic, and lumbar segments with spinal cord compression and cystic lesions. CSF immunology was initially positive for cysticercus cellulosae. After disease progression a meningeal biopsy was compatible with IgG4 related disease. The patient had partial response to rituximab and needed multiple surgical procedures for spinal cord decompression and CSF shunting.

CONCLUSIONS

This case highlights the possibility of IgG4-related disease in patients with diffuse pachymeningitis causing spinal cord compression, even with cystic lesions on MRI. Diagnosis of IgG4-related pachymeningitis is paramount due to the possibility of treatment response to immunotherapy, particularly to anti-CD20 agents.

Sino-Orbital IgG4 Related Disease- An Uncommon Entity

IgG4 related disease (IgG4-RD) is an auto immune fibro-inflammatory condition, characterised by presence of IgG4 positive lymphoplasmacytic infiltrates and extensive fibrosis of the involved organ. It commonly affects pancreas, biliary tract and salivary glands. Sino-orbital involvement is a relatively rare presentation. There is extensive fibrosis of the involved organ. Biopsy is often diagnostic and it shows extensive necrosis and lymphoplasmocytic infiltrates. They show dramatic response to steroid therapy. Here we present three cases of IgG4-RD disease involving orbit and para nasal sinuses who were evaluated and treated in a tertiary care teaching hospital over a period of 2 years.

IgG4-Related Disease (IgG4-RD) with Unique Combined Generalized Skin Rashes and Biliary Tract Manifestation: A Comprehensive Immunological Analysis

IgG4-RD is a multisystem fibroinflammatory disease characterized by the infiltration of tissues by IgG4 plasma cells. Combined skin and biliary tract involvement in IgG4-RD has not been described. We present perhaps the most comprehensive analysis of lymphocyte subsets in the first case of IgG4-related generalized skin rash and first case of combined skin and biliary tract manifestations. A 55-year-old male presented with painful jaundice and generalized macular pigmented pruritic eruptions, and CT abdomen revealed biliary obstruction. Ampulla and skin biopsies were subjected to histology and immunostaining. Naïve, central memory (TCM), effector memory (TEM), terminally differentiated effector memory (TEMRA) subsets of CD4+ and CD8+ T cells, T follicular helper subsets, naïve, transitional, marginal zone (MZ), germinal center (GC), IgM memory, and class-switched memory (CSM) B cells, and T follicular regulatory, regulatory B cells, CD4 Treg, and CD8 Treg were analyzed. Serum IgG4 was elevated at 448 mg/dL. Ampula biopsy showed lamina propria fibrosis and increased IgG4-positive plasma cells. Skin punch biopsy showed lymphoplasmacytic infiltrates with a 67% ratio of IgG4+:IgG+ plasma cells. CD4+TN and CD4+TCM decreased, whereas CD4+TEM increased. Naïve B cells increased; transitional, MZ, CSM, GC B cells, and plasmablasts decreased compared to control. CD4 Treg increased, whereas CD8 Treg and Breg decreased. In conclusion, IgG-RD may present with combined biliary tract and generalized dermatological manifestations. Changes in regulatory lymphocytes suggest their role in the pathogenesis of IgG4-RD.

The 2023 revised diagnostic criteria for IgG4-related ophthalmic disease

Immunoglobulin G4 (IgG4)-related disease is a clinical entity characterized by elevated serum IgG4 concentrations and infiltration of IgG4-immunopositive plasmacytes in various organs, including ophthalmic lesions. Diagnostic criteria for IgG4-related ophthalmic disease (IgG4-ROD) were established in 2014 and describe the most affected ocular adnexal tissues such as lacrimal glands, trigeminal nerves and extraocular muscles, but do not mention optic neuropathy, the most severe indication of ophthalmic lesions. We reviewed published case reports of optic neuropathy in IgG4-related disease (n = 44), and in many cases, decreased visual acuities recovered well following treatment such as systemic corticosteroids, rituximab, and orbital surgery. However, some patients did not recover, especially when pretreatment visual acuities were as low as light perception or less. Herein, we propose a 2023 revised diagnostic criteria for IgG4-ROD, which include a reminder not to overlook optic neuropathy. The 2014 diagnostic criteria specify mucosa-associated lymphoid tissue (MALT) lymphoma as an important differential diagnosis for the relationship between IgG4-ROD and orbital lymphoma. The 2023 revision directs physicians' attention toward lymphomas other than MALT lymphoma, considering that the 2014 criteria might have placed too much emphasis on MALT lymphoma.

Renal Manifestations of IgG4-Related Disease: A Concise Review

IgG4-related disease (IgG4-RD) is an immune-mediated disorder marked by fibro-inflammatory masses that can infiltrate multiple organ systems. Due to its relatively recent discovery and limited understanding of its pathophysiology, IgG4-related disease may be difficult to recognize and is consequently potentially underdiagnosed. Renal involvement is becoming regarded as one of the key features of this disease. To date, the most well-recognized renal complication of IgG4-related disease is tubulointerstitial nephritis, but membranous glomerulonephritis, renal masses, and retroperitoneal fibrosis have also been reported. This concise review has two objectives. First, it will briefly encapsulate the history, epidemiology, and presentation of IgG4-related disease. Second, it will examine the reported renal manifestations of IgG4-related disease, exploring the relevant histology, imaging, clinical features, and treatment considerations. This synthesis will be highly relevant for nephrologists, rheumatologists, general internists, and renal pathologists to raise awareness and help improve early recognition of IgG4-related kidney disease (IgG4-RKD).

Recent advances in IgG4-related autoimmune pancreatitis

The incidence of IgG4-related autoimmune pancreatitis (IgG4-AIP) is high in Asia and other countries, and unnecessary treatment is often undertaken due to both missed diagnosis and misdiagnosis in clinical practice. Although IgG4-AIP has attracted increasing attention, the details of IgG4-AIP pathogenesis and systemic immune response, including its relationship to tumor pathogenesis, are still unclear. In recent years, research on serum immunological detection, pathological features, clinical manifestations, diagnosis and treatment measures for IgG4-AIP has gradually increased. It is of great importance to summarize and discuss the latest progress regarding IgG4-AIP disease.

IgG4-related disease: an update on pathology and diagnostic criteria with a focus on salivary gland manifestations

Immunoglobulin G4-related disease (IgG4-RD) is a multi-organ disorder characterized by a highly variable clinical presentation depending on the affected organ/s, extent of tumefactive fibroinflammatory lesions, and associated functional impairment. The disease pursues a chronic, relapsing, often asymptomatic course and hence may pose a significant diagnostic challenge. Diagnostic delay can lead to progressive fibrosis and irreversible organ damage resulting into significant morbidity and even mortality. Given its broad clinical spectrum, physicians of all specialties may be the first clinicians facing this diagnostic challenge. Outside the pancreatobiliary system, the head and neck represents the major site of IgG4-RD with variable organ-specific diffuse or mass-forming lesions. In up to 75% of cases, elevated serum IgG4 levels are observed, but this figure possibly underestimates the fraction of seronegative cases, as the disease manifestations may present metachronously with significant intervals. Together with negative serology, this can lead to misdiagnosis of seronegative cases. A standardized nomenclature and diagnostic criteria for IgG4-RD were established in 2012 and revised in 2020 facilitating scientific research and expanding the range of diseases associated with IgG4 abnormalities. In addition to orbital pseudotumor, dacryoadenitis, Riedel thyroiditis, sinonasal manifestations, and rare miscellaneous conditions, IgG4-related sialadenitis is one of the most frequent presentations in the head and neck region. However, controversy still exists regarding the relationship between sialadenitis and IgG4-RD. This review focuses on the clinicopathological features of IgG4-related sialadenitis and its contemporary diagnostic criteria.

Mimickers of immunoglobulin G4-related hepatobiliary disease on biopsy

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

IgG4-related kidney disease: Clinicopathologic features, differential diagnosis, and mimics

IgG4-related kidney disease (IgG4-RKD) encompasses all forms of kidney disease that are part of IgG4-related disease (IgG4-RD). First recognized as IgG4-related tubulointerstitial nephritis (IgG4-TIN), and then IgG4-related membranous glomerulonephritis (IgG4-MGN), we now recognize additional patterns of interstitial nephritis, glomerular disease, and vascular disease that can be seen as part of IgG4-RKD. The clinical presentation is variable and can include acute or chronic kidney injury, proteinuria or nephrotic syndrome, mass lesion(s), and obstruction. While usually associated with other organ involvement by IgG4-RD, kidney-alone involvement is present in approximately 20 % of IgG4-RKD. Compared to IgG4-RD overall, patients with IgG4-RKD are more likely to show increased serum IgG4 or IgG, and more likely to have hypocomplementemia. In this review, we extensively cover other types of autoimmune and plasma cell-rich interstitial nephritis, mass forming inflammatory diseases of the kidney, and other mimics of IgG4-TIN, in particular ANCA-associated disease.

Treatment approaches in autoimmune pancreatitis (Review)

Autoimmune pancreatitis (AIP) is a rare disease. There are two distinct types of AIP: AIP type 1 (AIP-1), a pancreatic manifestation of a multi-organ disease linked to immunoglobulin (Ig)G4, and AIP type 2 (AIP-2), a pancreas-specific disease unrelated to IgG4. The usual course of treatment for AIP is oral corticosteroid medication. Rituximab has also been recommended for recurrent AIP-1 in order to initiate remission and provide ongoing treatment. Immunomodulators such as azathioprine are used to keep certain patients in remission. Evaluation also takes into account a number of pharmacological alternatives, including biologic drugs like anti-tumor necrosis factor therapy, a safe and efficient second-line treatment for AIP-2 relapse or steroid dependence. Corticosteroids and immunosuppressants, which are poorly tolerated due to considerable side effects, are being replaced by other biologic drugs, which may offer a beneficial therapeutic alternative.

Assessment of specificity of dermatopathologic criteria for IgG4-related skin disease

BACKGROUND

IgG4-related disease (IgG4-RD) represents a recently characterized multisystemic fibroinflammatory condition that can manifest a spectrum of skin findings (IgG4-related skin disease; IgG4-RSD). Histopathologic and immunohistochemical criteria have been proposed; however, the specificity of these criteria merits scrutiny given the potential histopathologic overlap of IgG4-RSD and both neoplastic and inflammatory skin conditions featuring lymphoplasmacytic infiltrates (IgG4-RSD mimics). This study sought to assess the specificity of the criteria by quantifying the frequency by which an expanded spectrum of IgG4-RSD mimics meet proposed thresholds.

METHODS

Following IRB approval, a total of 69 cases of IgG4-RD mimics, representing 14 different diagnoses featuring plasma cells, were reviewed and analyzed for the following histopathologic and immunohistochemical features: (i) maximum IgG4+ count/high-powered field (hpf) >200; (ii) IgG4/IgG ratio >0.4 averaged over 3 hpfs; (iii) IgG4+ count >10 per hpf.

RESULTS

Screening for IgG4-RSD by histopathologic criteria demonstrated the high frequency of lymphoplasmacytic infiltrates, contrasted with the rarity of storiform fibrosis (only one case of erythema elevatum diutinum [EED]) and obliterative phlebitis (0 cases). By immunohistochemical criteria, the analysis revealed that no cases exceeded 200 IgG4+ cells; 13% (9/69) cases demonstrated an IgG4/IgG ratio of >0.4 averaged over 3 hpfs; and 23% (16/69) cases demonstrated a mean IgG4+ count of >10 per hpf.

CONCLUSION

Application of proposed IgG4-RSD histopathologic criteria to an expanded spectrum of potential IgG4-RSD mimics (to include cutaneous marginal zone lymphoma, syphilis, necrobiosis lipoidica, lichen sclerosus, ALHE, psoriasis, lymphoplasmacytic plaque, EED, and erosive pustular dermatosis), highlights the relative nonspecificity of lymphoplasmacytic infiltrates contrasted with the stringency of storiform fibrosis and obliterative fibrosis. Furthermore, an IgG4+ cell count of >10 per hpf and an IgG4/IgG ratio of >0.4 are not specific to IgG4-RSD alone. In the appropriate clinical context for IgG4-RSD, histopathologic features still represent the entry threshold for diagnosis consideration, which then allows for further screening by immunohistochemical criteria.

Intracranial inflammatory pseudotumour related to IgG4: A very rare case

Background

Intracranial inflammatory pseudotumours (IPT) are rare entities that frequently lead to misdiagnosis with malignant lesions. The identification of these lesions is difficult, but important to avoid inadvertent iatrogenicity and to adjust therapeutic protocols.

Case Presentation

We report the case of a 30-year-old man who presented a single tonic-clonic seizure. Brain imaging showed a right frontal lesion with intra and extra axial components. Facing the radiologic presentation, a brain tumor was suspected, thus the patient underwent surgery. Pathological exam concluded to a plasma cell granuloma. A whole-body CT-scan showed only a thoracic aortitis. Complete blood work studies came back negative. The patient was also tested for an array of antibodies among which antinuclear antibodies were positive (blood level superior to 1/100). CSF evaluation revealed clear fluid with normal glucose concentration, normal protein levels and lymphocytic pleocytosis. Finally, IgG-4 plasma levels were elevated which led to the diagnosis of an IgG4-RD. The patient was put under prednisolone with a favorable outcome.

Conclusion

IPT have several etiologies, among which IgG4 related disease may be one of the less known as only 2 cases have previously been reported. Herein, we report a new case of a young man who presented for seizures related to an intracranial lesion of an IgG4 related disease. The challenge is to suspect such conditions to avoid unnecessary surgeries.

[Autoimmune pancreatitis versus pancreatic cancer]

CLINICAL ISSUE

Autoimmune pancreatitis (AIP) is classified as a distinct form of pancreatitis according to the guidelines. It is characterized by imaging morphologic and histologic features and is associated with extrapancreatic manifestations in type 1 IgG 4-associated disease. Symptoms and findings almost always improve with administration of steroids. Differentiation from pancreatic ductal adenocarcinoma is required, particularly in the presence of AIP with focal parenchymal involvement.

STANDARD RADIOLOGIC PROCEDURES

If AIP is suspected, abdominal ultrasound and/or endosonography, computed tomography (CT), and preferably magnetic resonance imaging (MRI) are indicated. A distinction is made between parenchymal and ductal changes that specifically indicate the presence of AIP.

METHODOLOGICAL INNOVATIONS AND EVALUATION

The diagnosis of autoimmune pancreatitis should be made based on the International Consensus Criteria (ICDC), in which the five main features (imaging, serology, histology, other organ involvement, response to steroid medication) are assessed. In type 1 AIP, typical imaging changes are sufficient to establish the diagnosis even with negative histology, whereas for type 2 AIP, histologic evidence is required. Imaging changes help in the differential diagnosis from pancreatic cancer.

PRACTICAL RECOMMENDATIONS

The following article addresses and evaluates crucial imaging diagnostic CT and MRI criteria for correct classification of findings, description of results, and differentiation of autoimmune pancreatitis from pancreatic cancer.

Immune-Mediated Hypertrophic Pachymeningitis and its Mimickers: Magnetic Resonance Imaging Findings

Hypertrophic pachymeningitis (HP) is a rare and chronic inflammatory disorder presenting as localized or diffuse thickening of the dura mater. It can be idiopathic or an unusual manifestation of immune-mediated, infectious, and neoplastic conditions. Although some cases may remain asymptomatic, HP can lead to progressive headaches, cranial nerve palsies, hydrocephalus, and other neurological complications, which makes its recognition a fundamental step for prompt treatment. Regarding the diagnosis workup, enhanced MRI is the most useful imaging method to evaluate dural thickening. This article addresses the MR imaging patterns of immune-mediated HP, including immunoglobulin G4-related disease, neurosarcoidosis, granulomatosis with polyangiitis, rheumatoid pachymeningitis, and idiopathic HP. The main infectious and neoplastic mimicking entities are also discussed with reference to conventional and advanced MR sequences.

[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.

IgG4-related digestive diseases: diagnosis and treatment

IgG4-related digestive diseases encompass a group of chronic inflammatory disorders characterized by autoimmune reactions and fibrosis affecting multiple digestive organs. These diseases are identified by elevated serum levels of IgG4 and the presence of IgG4-positive plasma cell infiltration in the affected sites, along with storiform fibrosis, obliterative phlebitis, and eosinophilic infiltration. Although extensive research has been conducted, a comprehensive understanding of these conditions remains elusive. Current clinical diagnosis often relies on the application of integrated diagnostic criteria for IgG4-related diseases, combined with specific organ involvement criteria. Distinguishing them from malignancies poses considerable challenges. Moreover, further investigations are required to elucidate the underlying pathogenic mechanisms and explore potential therapeutic interventions. This review provides a systematic classification of IgG4-related digestive diseases while discussing their diagnostic strategies, clinical presentations, and treatment modalities. The comprehensive insights shared herein aim to guide clinicians in their practice and contribute to the advancement of knowledge in this field.

Autoimmune Pancreatitis Type 1 with Biliary, Nasal, Testicular, and Pulmonary Involvement: A Case Report and a Systematic Review

INTRODUCTION

Immunoglobulin G4-related disease (IgG4-RD) is an immune-mediated condition associated with fibroinflammatory lesions that can occur at almost any anatomical site. It often presents as a multiorgan disease that may mimic malignancy, infection, or other immune-mediated conditions. Autoimmune pancreatitis (AIP) type 1 is the most prominent manifestation of IgG4-RD in the digestive tract, with common extra-pancreatic inflammation. We present the first patient with AIP and involvement of the testicles and nasal cavity.

PATIENT AND METHODS

A case of a patient with AIP type 1 and other organ involvement (bile ducts, testicles, nasal polyps, and lungs) is described. Additionally, a systematic review of AIP type 1 with testicular and nasal involvement was conducted.

RESULTS

The systematic review found two cases of AIP type 1 with testicular involvement and 143 cases with AIP type 1 with nasal cavity involvement. None of them had both testicular and nasal involvement.

CONCLUSIONS

This is the first case of AIP type 1 with other organ involvement, including testicular and nasal involvement, to be described. The number of patients with nasal and testicular involvement described in the literature is low. Creating awareness of this rare clinical condition is necessary, especially due to the very effective available treatment with corticosteroids and rituximab.

Idiopathic multicentric castleman's disease mimicking immunoglobulin G4-related disease responding well to Bortezomib: a case report

BACKGROUND

Castleman's disease (CD) is a rare disease that has clinical and pathological similarities to lymphoma and is characterized by a high frequency of associated immunological dysfunction. ImmunoglobulinG4-related disease (IgG4-RD) is a collection of systemic disorders that affect numerous organs and are also referred to as IgG4-associated sclerosing diseases. CD and IgG4-RD are difficult to separate because they may manifest similar commin clinical features.

CASE PRESENTATION

This case describes a 53-year-old female who, during routine medical check-up, exhibited a progressive increase in serum globulin levels and a simultaneous worsening of anemia symptoms, raising concern for a clonal plasma cell disease such as myeloma. However, bone marrow punctures did not reveal any abnormal plasma cells. Also, serum and urine immunofixation electrophoresis demonstrated no abnormal monoclonal protein bands. In addition, several laboratory findings excluded chronic liver disease, chronic infections caused by bacteria or viruses. Later, we found elevated serum IgG4 levels (10,700 mg/L), and identified multiple enlarged lymph nodes throughout the patient's body. Axillary lymph node aspiration revealed no abnormal lymphocytes, ruling out the possibility of lymphoma. Pathological morphology of the axillary lymph revealed a large number of plasma cells in the lymphatic follicles. In addition, there was a reduction in lymphatic follicle size and apoptosis of the germinal centres. Immunohistochemistry revealed IgG4+/IgG + in > 40% of cells, and more than 100 IgG4 + cells per high powered field (HPF) of specimen. As of now, finding strongly suggested IgG4-RD. This patient was treated with glucocorticoids and various immunosuppressive drugs, such as prednisone, cyclosporine, methotrexate, cyclophosphamide, mycophenolate mofetil, azathioprine and hydroxychloroquine. Unfortunately, the patient did not recover. Ultimately, idiopathic multicentric Castleman disease (iMCD) was diagnosed in relation to the patient's clinical presentation and laboratory tests, and after combination chemotherapy (VCD: Bortezomib, Cyclophosphamide and Dexamethasone), durable remission was achieved without serious adverse effects. During the follow-up period of one year and ten months, the patient remained stable.

CONCLUSION

The diagnosis of Castleman must be distinguished from other disorders such as IgG4-RD, malignant lymphoma, reactive hyperplasia of various lymph nodes (mostly caused by viral infections), plasmacytoma, advanced HIV and rheumatic diseases. Besides observing systemic symptoms, laboratory tests such as immunoglobulin levels, complement levels, interleukin levels, and C-reactive protein levels should also be performed in order to determine a diagnosis.

Relapse rate and predictors of relapse after cessation of glucocorticoid maintenance therapy in type 1 autoimmune pancreatitis: a multicenter retrospective study

BACKGROUND

Type 1 autoimmune pancreatitis responds well to glucocorticoid therapy with a high remission rate. Moreover, glucocorticoid maintenance therapy can help prevent relapse. However, the relapse rate following cessation of long-term glucocorticoid therapy is unknown. The aim of this study was to clarify the relapse rate and predictors of relapse following long-term glucocorticoid therapy cessation.

METHODS

We analyzed 94 patients who achieved remission after undergoing glucocorticoid therapy, discontinued treatment after at least 6 months of maintenance therapy, and were subsequently followed up for at least 6 months. The patients were divided into three groups based on treatment duration (< 18, 18-36, and ≥ 36 months), and their relapse rates were compared. Univariate and multivariate analyses of clinical factors were conducted to identify relapse predictors.

RESULTS

After discontinuing glucocorticoid therapy, relapse was observed in 43 (45.7%) patients, with cumulative relapse rates of 28.2% at 1 year, 42.1% at 3 years, 47.0% at 5 years, and a plateau of 77.6% at 9 years. Of the 43 patients who relapsed, 25 (58.1%) relapsed within 1 year after after cessation of glucocorticoid therapy. Relapse and cumulative relapse rates did not differ significantly according to treatment duration. In the multivariate analysis, an elevated serum IgG4 level at the time of glucocorticoid cessation was found to be an independent predictor of relapse (hazard ratio, 4.511; p < 0.001).

CONCLUSIONS

A high relapse rate occurred after cessation of glucocorticoid maintenance therapy, regardless of the duration of maintenance therapy, especially within the first year after cessation. However, the normalization of long-term serum IgG4 levels may be a factor in considering cessation.

IgG4-Related Diseases Involving Bilateral Renal Pelvises Successfully Treated with Steroid Therapy

Immunoglobulin (Ig) G4-related diseases are very rare diseases and are difficult to diagnose and treat. Here, we report a rare condition, an IgG4-related disease involving the bilateral renal pelvises, which was successfully treated with steroid therapy. A 64-year-old female was admitted with left flank pain and hematuria. Computed tomographic images showed irregular enhancing masses around the bilateral renal pelvises and lymph nodes in the left para-aortic area. A histopathological examination of a renal needle biopsy revealed numerous cells that were positive for IgG and more than 10 IgG4-positive cells per high-powered field. The IgG4/IgG ratio was more than 40%. Her serum IgG4 level was elevated to 1440 mg/dL, and her IgG4/IgG ratio was 82.1%. After a diagnosis of IgG4 sclerosing disease, a double-J ureteral stent was inserted and steroid therapy was performed for 20 weeks. Her symptoms dramatically improved, and the follow-up images showed a resolved state. There was no relapse of the disease for more than 6 months after the removal of the stent.

Saliva biomarkers in oral disease

Saliva is a versatile biofluid that contains a wide variety of biomarkers reflecting both physiologic and pathophysiologic states. Saliva collection is noninvasive and highly applicable for tests requiring serial sampling. Furthermore, advances in test accuracy, sensitivity and precision for saliva has improved diagnostic performance as well as the identification of novel markers especially in oral disease processes. These include dental caries, periodontitis, oral squamous cell carcinoma (OSCC) and Sjögren's syndrome (SS). Numerous growth factors, enzymes, interleukins and cytokines have been identified and are the subject of much research investigation. This review highlights current procedures for successful determination of saliva biomarkers including preanalytical factors associated with sampling, storage and pretreatment as well as subsequent analysis. Moreover, it provides an overview of the diagnostic applications of these salivary biomarkers in common oral diseases.

IgG4-related sclerosing thyroiditis (Riedel-Struma): a review of clinicopathological features and management

We present a thorough review of the literature on Riedel thyroiditis (RT) with emphasis on aetiology, diagnosis and management, using the PubMed, Sinomed, and China National Knowledge Infrastructure databases. Although the exact aetiology of RT remains obscure, the histopathological features are consistent with a localized form of IgG4-related systemic disease (IgG4-RSD). Nevertheless, IgG4-RSD as a systemic fibroinflammatory disorder per se rarely affects the thyroid in the context of multiorgan manifestations. The initial diagnosis of RT is based on clinical history and imaging, but confirmation by histopathological examination is mandatory. In contrast to the historical surgical approach, glucocorticosteroid therapy is currently considered first line therapy, in line with the RT currently being viewed as a manifestation of, or analogous to, IgG4-RSD. For disease relapse, immunomodulatory agents (azathioprine, methotrexate, rituximab) can be used.

Decoding the Clinical Significance of Immunoglobulin G4 in Rheumatoid Arthritis

Immunoglobulin (Ig) G4 accounts for 4-6% of the total IgG in a healthy human. Several evidence-based studies have suggested that the level of IgG4 is significantly elevated in autoimmune diseases, including rheumatoid arthritis (RA). The clinical significance of IgG4 in RA with regard to disease activity, severity, and treatment response remains elusive. We consecutively recruited 174 patients with RA from our rheumatology clinic. All subjects were assessed for their disease activity based on DAS28, radiographic joint damage based on the Modified Sharp Score (MSS), the functional capacity based on the Health Assessment Questionnaire -Disability Index (HAQ-DI), and treatment responsiveness using the European League Against Rheumatism (EULAR) response criteria. The serum IgG4 of the recruited subjects was measured via the ELISA test. The mean serum IgG4 level was 60.23 ± 30.08 mg/dL. We found that serum IgG4 had significant positive correlations with disease activity (r = 0.406; p < 0.001), ESR (r = 0.155; p = 0.041), CRP (r = 0.269; p < 0.001), joint damage (r = 0.195; p = 0.012) and functional disability (r = 0.909; p < 0.001). Subjects with elevated IgG4 (IgG4 > 86 mg/dL) had significantly higher ESR, CRP, HAQ-DI, and DAS 28 and a poorer treatment response compared to the group with non-elevated IgG4. After multivariate analysis, only HAQ-DI (OR = 4.229, 95% CI 1.302, 15.751, p = 0.018) and DAS28 (OR = 3.743, 95% CI 1.062, 13.193, p = 0.040) remained significantly associated with elevated serum IgG4. The preliminary findings of this study could suggest serum IgG4 to be a potential biomarker of disease activity and functional disability in RA.

Epiduritis related to IgG4 disease: A very rare cause for spinal cord compression

Background

Inflammatory pseudotumors are rare, and those attributed to immunoglobulin G4 (IgG4) diseases are even less frequently encountered. Here, we reviewed 41 cases from the literature of spinal inflammatory pseudotumors due to IgG4 and have added our single new case.

Case Presentation

A 25-year-old male presented with progressive back pain, bilateral paraparesis, and sphincter dysfunction. His deficit was attributed to MR-documented posterolateral lesion between the T5 and T10 levels for which he levels underwent a T1-T1010 laminectomy. The pathology revealed an immunoglobulin G4-related inflammatory pseudotumor. Postoperatively, the patient additionally required systemic and epidural administration of glucocorticoids.

Conclusion

IgG4-related disease is an emerging clinical condition that rarely involves the central nervous system. Spinal inflammatory pseudotumors, including IgG4 disease, should be more commonly considered among the potential differential diagnoses of lesions compressing the spinal cord.

Clinical presentation and organ-based outcomes of Multifocal fibrosclerosis: A systematic review

Objectives

Multifocal fibrosclerosis is a rare disorder causing progressive fibrosis of multiple organ systems. Existing data on the disease show that there are multiple manifestations of the disease, with different outcomes. However, quantitative data are scarce, prompting the need for our investigation.

Method

A comprehensive systematic review was performed from inception to November 16, 2022, with the restriction of English language, not including review articles. Article screening and extraction was performed independently, and shortlisted articles were assessed for bias. Analysis was performed using SPSS Version 25 (IBM® SPSS® Statistics; Chicago, IL, USA). Data were presented as frequencies and percentages, with a confidence interval of 95%.

Result

This review included 134 patients, with 78 (58.2%) males. Mean age was 53.6 years and included two pediatric patients. The most common comorbidity was diabetes (9.7%). Prevalent presenting symptoms included pain (47.8%) and swelling (35.1%). A mean of 2.51 organs or anatomical sites was affected, retroperitoneum (64.2%) being most affected. The pancreas (30.0%) and digestive system (47.0%) were the organs/organ systems most affected. Patients had favorable outcomes in 79.1% of cases, 87.3% had no relapse, and 91.8% of patients survived the condition.

Conclusion

The findings in this study provide a quantitative measurement of the demographics, presentations, organ manifestations, and outcomes of multifocal fibrosclerosis. We found the disease to be prevalent in males in Japan or the United States, with the abdomen and its organs being commonly involved.

Hypertrophic pachymeningitis due to IgG4-related disease (RD-IgG4). A case report

INTRODUCTION

Hypertrophic pachymeningitis (HP) is a clinico-radiological entity characterized by a thickening of the dura mater that may be focal or diffuse and manifested by a variety of neurological syndromes. Aetiologically, it is classified as infectious, neoplastic, autoimmune, and idiopathic. Many of these formerly idiopathic cases have been shown to fall into the spectrum of IgG4-related disease.

OBJECTIVE

To describe the case of a patient attended for neurological involvement due to hypertrophic pachymeningitis with initial diagnosis of inflammatory myofibroblastic tumour and final diagnosis of IgG4-related disease.

CASE

A 25-year-old woman with neurological symptoms of 3 years' evolution characterized initially by right hypoacusis, evolving with headache and diplopia. Magnetic resonance imaging (MRI) of the encephalon showed pachymeningeal thickening with involvement of vasculo-nervous structures in the tip of the cerebellum, cavernous sinus, ragged foramen, and optic chiasm. The patient presented for consultation with the result of an incisional biopsy that reported a proliferative lesion combining fibrous elements of fascicular or swirling arrangement with collagenized streaks with dense, lymphoplasmacytic infiltrate and some macrophages, with negative staining for ALK 1, with a diagnosis of inflammatory myofibroblastic tumour. Due to suspicion of IgG4-related disease (IgG4-RD) the biopsy was sent for review and pertinent complementary studies were requested.

BIOPSY REVIEW

Non storiform fibrosis, predominantly lymphoplasmacytic infiltrate, histiocytes, and polymorphonuclear infiltrate in sectors, without granulomas or atypia. Staining for germs negative. Immunohistochemistry with 50-60 IgG4+/HPF cells and range of 15%-20%, CD68⁺ in histiocytes, CD1a^-, S100^-. The patient presented deterioration of visual acuity due to ophthalmic nerve involvement, so glucocorticoid treatment was started in pulses and rituximab with regression of symptoms and imaging improvement of the lesions.

CONCLUSION

HP is a clinical imaging syndrome with variable symptoms and aetiologies that poses a diagnostic challenge. In this case the initial diagnosis was inflammatory myofibroblastic tumour, which is a neoplasm of variable behaviour, locally aggressive, and can metastasize; it is one of the main differential diagnoses of IgG4-related disease because they share anatomopathological features, including storiform fibrosis. IgG4-RD is an immune-mediated condition that can have single or multiple involvement. Its diagnosis is complex when it presents with single organ involvement or in non-typical organs (CNS, meninges) in which data are scarce, as in the case of our patient with single organ involvement of the CNS. Although there are classification criteria to guide non-specialists in the diagnosis, the sum of the clinical picture, imaging, laboratory, pathological anatomy, and immunohistochemistry will always be evaluated together for a definitive diagnosis.

A Clinical and Pathophysiological Overview of Intestinal and Systemic Diseases Associated with Pancreatic Disorders: Causality or Casualty?

The relationship between chronic intestinal disease, including inflammatory bowel disease (IBD) and celiac disease (CelD), and pancreatic disorders has been little investigated. Although an increased risk of acute pancreatitis (AP), exocrine pancreatic insufficiency with or without chronic pancreatitis, and chronic asymptomatic pancreatic hyperenzymemia have been described in these patients, the pathogenetic link remains unclear. It may potentially involve drugs, altered microcirculation, gut permeability/motility with disruption of enteric-mediated hormone secretion, bacterial translocation, and activation of the gut-associated lymphoid tissue related to chronic inflammation. In addition, the risk of pancreatic cancer seems to be increased in both IBD and CelD patients with unknown pathogenesis. Finally, other systemic conditions (e.g., IgG4-related disease, sarcoidosis, vasculitides) might affect pancreatic gland and the intestinal tract with various clinical manifestations. This review includes the current understandings of this enigmatic association, reporting a clinical and pathophysiological overview about this topic.

Comparison of the long-term outcomes between proximal and distal IgG4-related sclerosing cholangitis: A multicenter cohort study

BACKGROUND AND AIMS

Immunoglobulin G4-related sclerosing cholangitis (IgG4-SC) is considered a biliary manifestation of IgG4-related diseases. However, there has been a controversy on the clinical outcomes according to the location of the involved bile duct. We therefore compared the clinical outcomes and long-term prognosis of IgG4-SC with proximal bile duct involvement (proximal IgG4-SC) and IgG4-SC with distal bile duct involvement (distal IgG4-SC).

METHODS

We reviewed the data of patients with IgG4-SC that were prospectively collected at 10 tertiary centers between March 2002 and October 2020. Clinical manifestations, outcomes, association with autoimmune pancreatitis (AIP), steroid-responsiveness, and relapse of IgG4-SC were evaluated.

RESULTS

A total of 148 patients (proximal IgG4-SC, n = 59; distal IgG4-SC, n = 89) were analyzed. The median age was 65 years (IQR, 56.25-71), and 86% were male. The two groups were similar in terms of jaundice at initial presentation (51% vs 65%; P = 0.082) and presence of elevated serum IgG4 (66% vs 70%; P = 0.649). The two groups showed significant differences in terms of steroid-responsiveness (91% vs 100%; P = 0.008), association with AIP (75% vs 99%; P = 0.001), and occurrence of liver cirrhosis (9% vs 1%; P = 0.034). During a median follow-up of 64 months (IQR, 21.9-84.7), the cumulative relapse-free survival was significantly different between the two groups (67% vs 79% at 5 years; P = 0.035).

CONCLUSIONS

Relapse of IgG4-SC frequently occurred during follow-up. Proximal IgG4-SC and distal IgG4-SC had different long-term outcomes in terms of steroid-responsiveness, occurrence of liver cirrhosis, and recurrence. It may be advantageous to determine the therapeutic and follow-up strategies according to the location of bile duct involvement.

Recent progress on the treatment of type 1 autoimmune pancreatitis and IgG4-related disease

IgG4-related disease (IgG4-RD) is a fibroinflammatory disorder recognized as a novel clinical entity with either synchronous or metachronous multiorgan involvement. Autoimmune pancreatitis (AIP) is classified into two types: type 1 AIP as a pancreatic manifestation of IgG4-RD and type 2 AIP with granulocytic epithelial lesion and occasional association with ulcerative colitis. Although the pathogenic mechanism still remains unclear, possible multipathogenic factors such as genetic factors, disease-specific or related antigens, and abnormal innate or adaptive immunity may be involved in the development of IgG4-RD. Many immunocytes including M2 macrophages, plasmablasts, B cells, and T-cells (Th2-CD4+T, follicular helper T-cells, and CD4+SLAMF7+cytotoxic T-cells) play important roles in the pathogenesis. Conventional induction and maintenance therapies with glucocorticoid or rituximab are recommended in all symptomatic patients with active IgG4-RD. In those at risk for irreversible damage in any organs, this should be done urgently, regardless of symptoms. As no randomized clinical trials other than glucocorticoid maintenance therapy for type 1 AIP have been performed, the comprehensive management for IgG4-RD has not been established yet. Targeted treatment approaches against the plasmablast to B cell lineage and the CD4+ SLAMF7+ cytotoxic T-cell seem to be promising for the future-directed treatment.

A case of reversible hypoparathyroidism in a patient with Riedel's thyroiditis treated with glucocorticoids

A 48-year-old woman with a history of primary hypothyroidism, presented with compressive symptoms secondary to a rapid enlargement of a preexisting goiter. She had no clinical signs of hypocalcemia. Biological tests revealed hypoparathyroidism. Cervicothoracic computed tomography scan showed a heterogeneous compressive goiter. The patient was treated with levothyroxine, calcium, and alfacalcidol. A total thyroidectomy was not performed because of the hard adhesion to neighboring structures. Histopathological examination of the thyroid biopsy was consistent with the diagnosis of Riedel's thyroiditis (RT). The patient was treated with glucocorticoids. The outcome was marked by the resolution of compressive symptoms and the decrease of the thyroid gland volume. Serum calcium and parathyroid hormone levels reached normal ranges after the discontinuation of vitaminocalcic supplementation. Hypoparathyroidism may be clinically asymptomatic in a patient with RT as in our case. Early administration of glucocorticoids may be effective in reducing the fibrosclerotic process and lead to the recovery of parathyroid dysfunction.

Orbital inflammatory pseudotumor revealing multi-organ immunoglobulin G4-related disease

Relatively recently, the concept that immunoglobulin G4 (IgG4)-related disease is a distinct chronic inflammatory disorder rather than a subset of Sjögren's syndrome has been accepted. IgG4-related disease (IgG4-RD) is a fibro-inflammatory systemic immune-mediated condition that can affect the pancreas, salivary glands, and lymph nodes. Almost every organ may be impacted synchronously or metachronously by this illness, which causes the development of sclerotic masses of varying sizes. Numerous other rheumatic diseases can present with characteristics of IgG4-RD, making it difficult to distinguish between them. However, cases of IgG4-RD involving the bilateral orbits, and pancreas with biological abnormalities are rare. We present a case of an 18-year-old female with vitiligo since the age of 3 years who presented with acute pancreatitis and acalculous cholecystitis, bilateral orbital masses, palpebral edema, and eosinophilia. The patient was diagnosed with IgG4-RD in keeping with clinical presentation and the elevated serum IgG4 level and after elimination of other differential diagnoses. The patient's symptoms gradually relieved after glucocorticoid therapy. This case presents an uncommon combination of clinical features infrequently reported in the literature. Multi-organ IgG4-RD is a multisystemic mass, commonly creating diagnostic challenges for clinicians. Furthermore, and more importantly, it highlights the need to keep a differential of IgG4-RD in mind, to aid in the early and correct treatment of the disease.

Thoracoabdominal manifestations of immunoglobulin G4-related disease

Immunoglobulin G4-related disease (IgG4-RD) comprises a group of immune-mediated diseases that, until recently, were considered separate entities. These entities have a similar clinical presentation, serological findings, and pathogenesis, so they are currently considered a single multisystemic disease. The common characteristic is the infiltration of involved tissues by plasma cells and lymphocytes that are positive for IgG4. Three major criteria have been proposed for the diagnosis of IgG4-RD: clinical, laboratory, and histological. The pancreas is the organ that is most affected by IgG4-RD, which can simulate a tumor. In this respect, a series of signs could help us suspect that the pancreatic findings do not reflect a tumor (halo sign, duct-penetrating sign, absence of vascular invasion, etc.). The differential diagnosis is important to avoid unnecessary surgical interventions.

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.

A case of type 2 autoimmune pancreatitis with spontaneous remission

A 70-year-old man with epigastric pain was referred to our hospital. Computed tomography and magnetic resonance imaging showed the diffusely enlarged pancreas compared to his normal pancreas 6 months prior to presentation. Serum levels of IgG4 and amylase were normal, while C-reactive protein was slightly elevated. Endoscopic ultrasound-guided fine-needle biopsy of the pancreas revealed acinar-ductal metaplasia with neutrophil infiltration and without infiltration of IgG4-positive plasma cells. After the clinical diagnosis of type 2 autoimmune pancreatitis (AIP), his symptoms spontaneously improved without steroid therapy. Three months later, radiological findings showed improved pancreas size and serological findings. The pathological diagnosis of type 2 AIP using endoscopic ultrasound-guided fine-needle biopsy is challenging, particularly for proving granulocyte epithelial lesions. This was a valuable type 2 AIP case in which the images before, at the time of onset, and at the time of spontaneous remission were evaluated.

Case report: Clinical highlights and radiological classification of IgG4-related spinal pachymeningitis: A rare case series and updated review of the literature

Purpose

Hypertrophic pachymeningitis associated with immunoglobulin G4-related disease (IgG4-RD) has been rarely reported, and there is little information and no clear consensus on the management of IgG4-related spinal pachymeningitis (IgG4-RSP). The present study described its possible clinical features, including the symptoms, imaging, treatment and prognosis of patients with IgG4-RSP.

Methods

We report three patients who presented with progressive neurological dysfunction due to spinal cord compression. Relevant articles were searched from the PubMed, Web of Science, and Embase databases, and the resulting literature was reviewed.

Results

The literature review provided a summary of 45 available cases, which included three cases from our center. Progressive worsening of neurological impairment was observed in 22 patients (48.9%). The lesions involved the thoracic spine (n=28, 62.2%), cervical spine (n=26, 57.8%), lumbar spine (n=9, 20.0%), and sacral spine (n=1, 2.2%). Furthermore, the lesions were located in the dura mater (n=18, 40.0%), epidural space (n=17, 37.8%), intradural-extramedullary space (n=9, 20.0%), and intramedullary space (n=1, 2.2%). On magnetic resonance imaging (MRI), the lesions generally appeared as striated, fusiform, or less often lobulated oval changes, with homogeneous (n=17,44.7%) and dorsal (n=15,39.5%) patterns being the most common. Thirty-five patients had homogeneous T1 gadolinium enhancement. Early surgical decompression, corticosteroid treatment, and steroid-sparing agents offered significant therapeutic advantages. A good therapeutic response to disease recurrence was observed with the medication.

Conclusion

The number of reported cases of IgG4-RSP remains limited, and patients often have progressive worsening of their neurological symptoms. The features of masses identified on the MRI should be considered. The prognosis was better with decompression surgery combined with immunosuppressive therapy. Long-term corticosteroid treatment and steroid-sparing agent maintenance therapy should be ensured. A systemic examination is recommended to identify the presence of other pathologies.

Bibliometric analysis of IgG4-related disease research from 2003 to 2022 based on Web of Science Core Collection Databases

This study aimed to perform a bibliometric analysis of the IgG4-related disease (IgG4-RD) research field over the past 20 years to explore its research hotspots and trends. The literature of IgG4-RD published in the Web of Science Core Collection databases was reviewed from January 1, 2003, to April 30, 2022. A bibliometric analysis was carried out using CiteSpace software to evaluate and visualize the evolving dynamics and hotspots in the field of IgG4-RD. A total of 3174 IgG4-RD articles were reviewed. Since 2011, there has been a rapid increase in published literature. Japan is the highest yielding country and Kanazawa University the highest yielding institution. The USA has the highest centrality (0.34) and plays a critical role in cooperation and communication of IgG4-RD research. Nine highly connected clusters of IgG4-RD were observed by keyword analysis. Research hotspots included IgG4-RD involved organs and differentiation from Rosai-Dorfman disease and primary sclerosing cholangitis. Further research topics include pathogenesis, relapse, and malignancy. As a cross-discipline systemic disease, IgG4-RD requires attention by clinicians in multiple fields. This bibliometric analysis can help researchers grasp trends and provide new perspectives for future research on IgG4-RD.

[Differential diagnosis of IgG4-related disease]

IgG4-related disease is a chronic autoimmune fibro-inflammatory disease characterized by the presence of lymphoplasmacytic infiltrate, storiform fibrosis, obliterating phlebitis, increased number of IgG4+ cells in tissue, and, in most cases, an elevated serum IgG4 level. This disease often affects the pancreas, salivary glands and lymph nodes, but can involve almost any tissue. Its etiology is still unclear, the central role in the pathogenesis belongs to B-lymphocytes, T2-helpers, interleukins 1-β, 4, 5, 10, 13 and tumor growth factor 1-β. The ambiguous clinical picture and frequent simultaneous involvement of several organs make it difficult to diagnose, so biopsy plays a leading role in making a diagnosis. The characteristic microscopic picture, the presence of certain populations of lymphocytes are key criteria in establishing the correct diagnosis.

Recent advances in the management of autoimmune pancreatitis in the era of artificial intelligence

Autoimmune pancreatitis (AIP) is a type of immune-mediated pancreatitis subdivided into two subtypes, type 1 and type 2 AIP. Furthermore, type 1 AIP is considered to be the pancreatic manifestation of the immunoglobulin G4 (IgG4)-related disease. Nowadays, AIP is increasingly researched and recognized, although its diagnosis represents a challenge for several reasons: False positive ultrasound-guided cytological samples for a neoplastic process, difficult to interpret levels of IgG4, the absence of biological markers to diagnose type 2 AIP, and the challenging clinical identification of atypical forms. Furthermore, 60% and 78% of type 1 and type 2 AIP, respectively, are retrospectively diagnosed on surgical specimens of resected pancreas for suspected cancer. As distinguishing AIP from pancreatic ductal adenocarcinoma can be challenging, obtaining a definitive diagnosis can therefore prove difficult, since endoscopic ultrasound fine-needle aspiration or biopsy of the pancreas are suboptimal. This paper focuses on recent innovations in the management of AIP with regard to the use of artificial intelligence, new serum markers, and new therapeutic approaches, while it also outlines the current management recommendations. A better knowledge of AIP can reduce the recourse to surgery and avoid its overuse, although such an approach requires close collaboration between gastroenterologists, surgeons and radiologists. Better knowledge on AIP and IgG4-related disease remains necessary to diagnose and manage patients.