The latest on IgG4-RD: a rapidly emerging disease. Curr Opin Rheumatol. 2012;24:60-69. [PMID: 22157413 DOI: 10.1097/BOR.0b013e32834ddb4a]

Bessel's disease-the first report of an IgG4-related disorder

Many aspects of IgG4-related diseases were initially described during the late 19th and early 20th century. A variety of clinical presentations caused by this common pathology have been named after the researchers who first described the disorders, such as Mikulicz, Küttner, Riedel or Ormond. However, the initial description of retroperitoneal fibrosis dates back to even 50 years earlier, when in 1846, the Prussian private practitioner Raphael Jakob Kosch described a hitherto unknown constellation of symptoms and pathological findings in a famous patient. This celebrity was the mathematician and astronomer Friedrich Wilhelm Bessel, a close friend of Alexander von Humboldt and Carl Friedrich Gauss.

AuntMinnie Fluorodeoxyglucose Positron Emission Tomography-Computed Tomography Leads to Diagnosis of Immunoglobulin G4-Related Disease

A 61-year-old male underwent fluorodeoxyglucose positron emission tomography-computed tomography (FDG PET-CT) for evaluation of fever and weight loss with clinical suspicion of occult malignancy or tuberculosis. The scan showed hypermetabolism in bilateral submandibular salivary glands, biliary radicles, pancreas, bilateral kidneys, prostate, and multiple lymph nodes. Based on the concomitant involvement of these sites, suspicion of immunoglobulin G4 (IgG4)-related disease was raised in PET-CT report. Further evaluation with serum IgG4 levels and histopathology of the submandibular salivary gland confirmed the diagnosis of IgG4-related disease. The ability of FDG PET-CT to evaluate the whole-body status of disease played a crucial role in this case.

Concomitant presentation of eosinophilic or oncocytic mucoepidermoid carcinoma, immunoglobulin G4-related disease, and adult-onset asthma and periocular xanthogranuloma: Case report of 3 uncommon clinical entities

RATIONALE

Immunoglobulin (Ig) G4-related disease (IgG4-RD) reportedly has a strong relationship with adult-onset asthma and periocular xanthogranuloma (AAPOX) and may be linked to sclerosing mucoepidermoid carcinoma (MEC). We present a rare case of IgG4-RD and AAPOX occurring in a patient with resected eosinophilic or oncocytic MEC.

PATIENT CONCERNS

A 52-year-old woman was referred to our rheumatology clinic in 2020 to be evaluated for suspected IgG4-RD.

DIAGNOSES

The patient had diagnoses of periorbital xanthelasmas, worsening glucocorticoid-dependent chronic rhinosinusitis and adult-onset asthma, and cervical lymphadenopathy persisting 2 years after resection of a low-grade MEC of a minor salivary gland.

INTERVENTIONS

Because the patient's symptomatic relief was glucocorticoid dependent, IgG4-RD was suspected, and she was referred to our medical center. Her amylase and lipase levels were elevated. Serum IgG4 levels were initially within normal limits, but IgG4-RD was diagnosed because of the presence of lymphadenopathy and evidence of pancreatitis, which was shown on positron emission tomography/computed tomography. Furthermore, the IgG4 levels later increased without explanation. After the patient began combination therapy with a glucocorticoid (prednisone) and methotrexate, her symptoms improved but recurred when the daily oral glucocorticoid dosage decreased below 10 mg. An excisional biopsy of her right submandibular gland in 2021 yielded results consistent with IgG4-RD. In addition, AAPOX was diagnosed, given the presence of periocular edema and plaques, adult-onset asthma, and rhinosinusitis.

OUTCOME

The patient was carcinoma free at last follow-up and was receiving medication to treat the other conditions.

LESSONS

The diagnosis of these 3 concomitant, uncommon entities required approximately 7 years of medical investigations. Clinicians should know that IgG4-RD, AAPOX, and MEC may occur together.

Orchestration of Immune Cells Contributes to Fibrosis in IgG4-Related Disease

This review summarizes recent progress in understanding the pathogenesis of IgG4-related disease (IgG4-RD), with a focus on fibrosis. Several studies reported that CD4+ T cells with cytotoxic activity promoted by the secretion of granzyme and perforin, cytotoxic CD4+ T cells (CD4+CTLs), and disease-specific activated B cells, infiltrated inflamed tissues and cooperated to induce tissue fibrosis in autoimmune fibrotic diseases such as IgG4-RD, systemic sclerosis, and fibrosing mediastinitis. An accumulation of cells undergoing apoptotic cell death induced by CD4+CTLs and CD8+CTLs followed by macrophage-mediated clearing and finally tissue remodeling driven by cytokines released by CD4+CTLs, activated B cells, and M2 macrophages may contribute to the activation of fibroblasts and collagen production. In IgG4-RD, this process likely involves the apoptosis of non-immune, non-endothelial cells of mesenchymal origin and subsequent tissue remodeling. In summary, CD4+CTLs infiltrate affected tissues where they may cooperate with activated B cells, CD8+CTLs, and M2 macrophages, to induce apoptosis by secreting cytotoxic cytokines. These immune cells also drive fibrosis by secreting pro-fibrotic molecules in IgG4-RD.

Concomitant adult onset xanthogranuloma and IgG4-related orbital disease: a rare occurrence

Adult onset xanthogranulomatous disease is a rare orbital disease. IgG4-related disease is a systemic disease that can often manifest in the orbit. In this communication, we present the case of a patient with a xanthelasma-like lesion on the upper eyelid, and an enlarged lacrimal gland, which on biopsy was diagnosed as an orbital xanthogranuloma. Detailed serological workup showed that the patient was found to have elevated serum IgG4 levels. The orbital specimen was re-stained and found to be positive for IgG4. The patient was treated with oral steroids with partial resolution of the lesion. This is an interesting case of both histopathological adult onset xanthogranuloma (AOX) and IgG4-related orbital disease (IgG4-ROD). The early evidence suggests that the diagnosis of one of these disorders should point the physician to investigate for the presence of the other, especially if xanthogranulomatous disease is diagnosed first.

Atypical IgG4-related disease limited to the sino-nasal cavity: A case report

Given the overlapping clinical features of sino-nasal immunoglobulin 4-related disease (IgG4-RD) to rhinitis or rhinosinusitis, this paper aims to delineate this rare, isolated manifestation significant to physicians for their daily practice and researchers contributing to this field.

Morphologic Cross-Sectional Imaging Features of IgG4-Related Orbitopathy in Comparison to Ocular Adnexal Lymphoma

Aim

To detect radiological features that, in addition to clinical findings, may aid in correct differentiation between IgG4-related ophthalmic disease (IgG4-ROD) and ocular adnexal lymphoma (OAL).

Methods

In this retrospective, single-center, comparative analysis, we compared cross-sectional imaging findings of 13 consecutive patients with histologically proven IgG4-ROD and a control group of 29 consecutive OAL-patients diagnosed between 10/2014 and 09/2019. Statistical significance was accepted at a p<0.05 significance level.

Results

IgG4-ROD-patients had longer time-to-diagnosis, higher orbital recurrence rates, but smaller lesions compared to OAL-patients (p=0.002; p=0.006 and p=0.006; Mann–Whitney U-test). Frequent cross-sectional imaging findings in both IgG4-ROD-patients and OAL-patients included extraocular muscle enlargement (92% and 93%, respectively; most often in the lateral rectus muscles and the levator-complex), and lacrimal-gland enlargement (85% and 83%, respectively). Other imaging findings comprised infraorbital nerve-involvement (IgG4-ROD, 23%, OAL, 17%) and orbital fat inflammation (IgG4-ROD, 23%, OAL, 28%). Bony infiltration and remodeling, heterogenous contrast-media distribution, and infiltration of the lacrimal system were seen slightly more often in IgG4-ROD (23%, 38%, 15% and 15% versus 17%, 14%, 3% and 7%). However, cross-sectional imaging features did not differ significantly between patient subgroups. Clinical symptoms predominantly occurred unilaterally (IgG4-ROD, 9/13, 69%, OAL, 24/29, 83%), while imaging findings were most often bilateral (IgG4-ROD, 11/13, 85%, OAL, 23/29, 79%, p<0.001, McNemar test).

Conclusion

No morphological cross-sectional imaging sign could reliably distinguish between IgG4-ROD and OAL, leaving histopathology indispensable for definite diagnosis. Yet, importantly, for both IgG4-ROD and OAL, cross-sectional imaging frequently detected bilateral orbital disease when only one eye was clinically affected.

A Case Series of Patients with Isolated IgG4-related Hypophysitis Treated with Rituximab

Context

The acute presentation of immunoglobulin G4 (IgG4)-related hypophysitis can be indistinguishable from other forms of acute hypophysitis, and histology remains the diagnostic gold standard. The high recurrence rate necessitates long-term immunosuppressive therapy. Rituximab (RTX) has been shown to be effective in systemic IgG4-related disease (IgG4-RD), but experience with isolated pituitary involvement remains limited.

Case Description

We report 3 female patients with MRI findings suggestive of hypophysitis. All patients underwent transsphenoidal biopsy and fulfilled diagnostic criteria for IgG4-related hypophysitis. Treatment with glucocorticoids (GCs) resulted in good therapeutic response in Patients 1 and 2, but the disease recurred on tapering doses of GCs. GC treatment led to emotional lability in Patient 3, necessitating a dose reduction. All 3 patients received RTX and Patients 2 and 3 received further courses of treatment when symptoms returned and B-cells repopulated. Patient 3 did not receive RTX until 12 months from the onset of symptoms. Patient 1 was not able to have further RTX treatments due to an allergic reaction when receiving the second dose. Rituximab treatment resulted in sustained remission and full recovery of anterior pituitary function in Patients 1 and 2, with complete resolution of pituitary enlargement. By contrast, Patient 3 only showed a symptomatic response following RTX treatment, but pituitary enlargement and hypofunction persisted.

Conclusion

Rituximab treatment for IgG4-related hypophysitis resulted in sustained remission in 2 patients treated early in the disease process but only achieved partial response in a patient with chronic disease, suggesting that early therapeutic intervention may be crucial in order to avoid irreversible changes.

Orbital Vasculitides-Differential Diagnosis

PURPOSE OF REVIEW

The orbit is subject to a variety of vascular insults that manifest with both specific and nonspecific patterns of vision compromise. The aim of the following review is to highlight the ophthalmic clinical features of systemic vasculitides that most frequently involve the orbit and differentiate them from the most common non-vasculitic orbital disorders.

RECENT FINDINGS

New studies continue to explore the autoimmune nature of vasculitic disease and seek to determine optimal use of newer therapies such as biologic agents. The pattern of ocular involvement in the context of clinical history allows the knowledgeable physician to distill a differential diagnosis into a specific or likely cause. Establishing a diagnosis in a timely fashion allows for a custom-tailored approach to therapy.

A case of immunoglobulin G4-related lung disease with bilateral diffuse infiltration: A case report

RATIONALE

Immunoglobulin (Ig) G4-related disease (IgG4-RD) is a rare and chronic progressive autoimmune disease. It is a novel clinical entity characterized by elevated serum IgG4 concentration and tissue infiltration by IgG4 plasma cells. IgG4-related lung disease (IgG4-RLD) has been described as interstitial pneumonia and inflammatory pseudotumor, with various abnormal radiographic patterns. We report a case of IgG4-related lung disease with bilateral diffuse infiltration.

PATIENT CONCERNS

A 65-year-old woman was admitted to our hospital because of cough, sputum, and fever. Chest computed tomography (CT) revealed multifocal areas of consolidations, nodules, and ground glass opacities in both lungs. She still had fever after anti-infective therapy.

DIAGNOSES

Bronchial bronchoscopy and percutaneous lung biopsy were performed, resulted in a pathological diagnosis of IgG4-RLD.

INTERVENTIONS

The patient was started on oral prednisolone 30 mg/day for 28 days, and then was gradually tapered.

OUTCOMES

After one week treatment, the temperature was stable, CT showed significant improvement in the areas of consolidations and nodules.

LESSONS

It is a typical case of IgG4-RLD. This case indicated that suggestive evidence, radiological appearances, serum tests, pathological characteristics, and classic therapy IgG4-RLD. It is a rare disease that needs our more attention in future.

The impact of IgG-4-ROD on the diagnosis of orbital tumors: A retrospective analysis

This study was to determine the prevalence of immunoglobulin G4 (IgG4)-related orbital disease (IgG4-ROD) among patients who have previously undergone biopsy and were diagnosed to have idiopathic orbital inflammatory disease (IOID) or orbital lymphoproliferative disease (OLD), namely, lymphoma and benign reactive lymphoid hyperplasia (BRLH). This is a retrospective cross-sectional study. The charts and slides of all patients who underwent biopsies and were histopathologically diagnosed to have either IOID or OLD were reviewed. Demographics, clinical features, initial histopathological diagnoses, treatment received, and final outcome were noted. Using the diagnostic criteria for diagnosis for IgG4 disease, those cases that would classify as "possible IgG4-related disease (IgG4-RD)" were reviewed, reclassified, and reassigned a diagnosis of IgG4-ROD. We reviewed 105 patients' clinical charts. Of these 105 patients, upon reviewing the histopathology, 18 (17.15%) patients were found to fit the diagnostic criteria for possible IgG4-ROD. Of these 18 patients who were now reassigned the diagnosis of IgG4-ROD, the most common previous histopathological diagnosis was found to be IOID, for eight patients (44%), then BRLH, which was noted in five patients (27.8%), followed by lymphoma, which was noted in two patients (11.1%). Previously diagnosed cases of IOID and OLD were found to fulfill the criteria for IgG4-ROD. Given the advent of recent diagnostic and histopathological techniques, all cases of suspected IOID and OLD should be screened for IgG4-ROD and all previously diagnosed cases must be closely followed up, given the systemic implication of IgG4-RD. Histopathological reassessment of previously diagnosed cases may be considered.

[Diseases of connective tissue in IgG4-associated autoimmune diseases]

The IgG4-associated diseases of connective tissue are caused by allergen-mediated autoimmune processes. The retroperitoneum, mesentery and mediastinum as well as other less common localizations, such as the neck, orbit and periarticular connective tissue can be affected. Inflammatory fibrosis is initially dominated by a lymphocytic and plasma cell-rich infiltrate and later by cell-poor storiform fibrosis. Stenosis and occlusion of vessels, ureters and intestines can cause severe complications. Computed tomography (CT) and magnetic resonance imaging (MRI) can be implemented in the diagnostic algorithm to narrow the differential diagnosis, delineate the distribution of fibrosis and reveal complications.

Study of systemic disease IgG4. Usefulness of 2-[18F]-fluoro-2-deoxy-D-glucose -positron emission tomography/computed tomography for staging, selection of biopsy site, evaluation of treatment response and follow-up

Immunoglobulin G4-related systemic disease (IgG4-RSD) is a recently emerging disorder characterized by swelling lesions with storiform fibrosis and lymphoplasmacytic infiltration enriched with IgG4-positive plasma cells. IgG4-RSD has been found in multiple organs/tissues. The diagnosis requires the integration of clinical, serological, imaging, histopathological, and immunohistological features. The 2-[18F]-fluoro-2-deoxy-D-glucose-positron emission tomography/computed tomography (18F-FDG PET/CT) enables the acquisition of whole-body images and provides functional information about disease activity. However, its current role in IgG4-RSD is not well established in clinical practice. In our case, we studied a patient with systemic symptoms, submaxillary adenopathy, and imaging explorations that initially guided toward a lymphoproliferative process. However, the differential diagnosis with an autoimmune systemic disease type IgG4 was considered because of elevated levels of serum immunoglobulins. The study was completed with 18F-FDG PET/CT that not only allowed us to assess the extension disease and to locate the best lesion for biopsy but also allowed us to evaluate the response to treatment and to diagnose the suspicion of recurrence. In this case, PET/CT shows its usefulness in clinical practice.

IgG4-Related Kidney Disease: Report of a Case Presenting as a Renal Mass

IgG4-related disease (IgG4-RD) is a nosological entity defined as a chronic immune-mediated fibro-inflammatory condition characterized by a tendency to form tumefactive, tissue-destructive lesions or by organ failure. Urologic involvement in IgG4-RD has been described in some short series of patients and in isolated case reports, most often involving the kidneys in so-called IgG4-related kidney disease (IgG4-RKD). The disease can occasionally mimic malignancies and is at risk of being misdiagnosed due to its rarity. We report the case of a 56-year-old man presenting with a right renal mass suspected of being malignant. Laboratory tests showed normal creatinine levels, a high erythrocyte sedimentation rate, and high levels of C-reactive protein and microalbuminuria. The patient underwent radical right nephroureterectomy and histopathologic examination revealed features proving IgG4-RKD. He was therefore referred to immunologists. Typical clinical presentation of IgG4-RKD includes altered renal function with inconstant or no radiologic findings. Conversely, in the case we presented, a single nodule was detected upon imaging evaluation, thus mimicking malignancy. This raises the issue of a proper differential diagnosis. A multidisciplinary approach can be useful, although in clinical practice the selection of patients suspected of having IgG4-RKD is critical in the cases presenting with a renal mass that mimics malignancy.

Granuloma Faciale and Eosinophilic Angiocentric Fibrosis: Similar Entities in Different Anatomic Sites

BACKGROUND

Eosinophilic angiocentric fibrosis (EAF) and granuloma faciale (GF) share several histopathologic features, including eosinophil-rich inflammation, microangiitis, and progressive fibrosis. Concurrent presentation of EAF and GF suggests a pathogenetic link between them.

OBJECTIVES

To identify histologic findings that tell them apart and construe the pathogenetic mechanisms behind each morphologic variable, 14 immunohistochemical markers were used to study the cells subpopulations in 14 cases of GF and 3 cases of EAF.

MATERIALS AND METHODS

The lesions were classified according to their stage of development. The antibodies studied were: CD4, Foxp3, CD8, granzymes A and B, perforin, granulysin, CD20, CD56, CD68, ICAM-1, CD34, CD105, and 1A4.

RESULTS

The intensity of the sclerotic response and the density of 1A4-immunostained cells were significantly higher in EAF. In both diseases, CD68 cells were the most numerous, followed by CD20, CD8, and CD4 cells. About 30% of cells expressed ICAM-1. Among cells with cytotoxic granules, granulysin-positive cells were the most frequent.

CONCLUSIONS

Differences between GF and EAF were found to be mostly like due to anatomic site (usually skin of the face vs. sinonasal cavity) and stage of the disease development (usually earlier in cutaneous lesions because of their visibility). Innate and adaptive immunity, including B cells, T cells, and cytotoxic granules have a role in their pathogenesis.

Clinicopathology of Immunoglobulin G4–Related Chronic Sclerosing Sialadenitis

Objectives

To investigate the clinicopathologic characteristics of patients with immunoglobulin G4–related chronic sclerosing sialadenitis (IgG4-RCSS), a recently recognized disease.

Study Design

Case series with chart review and pathology study.

Settings

Tertiary care hospital.

Subjects and Methods

We evaluated chronic sialadenitis specimens obtained over 11 years using pathologic examination and IgG4 immunohistochemistry staining. The specimens were assigned a revised diagnosis of IgG4-RCSS or chronic sialadenitis not otherwise specified, and clinicopathologic data from each group were compared.

Results

Of the 84 patients, 21 were diagnosed with IgG4-RCSS and 63 with chronic sialadenitis not otherwise specified. IgG4-RCSS patients were older (68.2 ± 13.9 vs 54.2 ± 15.8 years, P = .001), predominantly male (85.7% vs 61.9%, P = .036), and more likely to present with painless swelling (75% vs 44.3%, P = .001) and bilateral involvement (52.4% vs 6.3%, P < .001). Ratio of IgG4-positive plasma cells to IgG-positive plasma cells in IgG4-RCSS tissues was 0.81 ± 0.14. The mean value of serum IgG4 in IgG4-RCSS patients was 918.8 mg/dL.

Conclusion

IgG4-RCSS is more common in older male patients and frequently presents with bilateral involvement. Informing head and neck surgeons of the clinical features of IgG4-RCSS and promoting a combined approach of clinical evaluation, imaging, and biopsy can improve the accuracy of preoperative diagnoses.

Immunoglobulin G4-related pleuritis - A case report

Immunoglobulin G4-related disease (IgG4-RD) is a chronic disease that presents with inflammation and fibrosis of involved tissue. It encompasses several disorders previously described using different terms, but all disorders are characterised by IgG4-positive plasma cells and lymphocytes infiltration of tissues. We report a rare case of a 58-year-old man with IgG4-related pleural disease without other systemic manifestations. The diagnosis was based on characteristic changes on PET-CT and typical histopathology in a pleural specimen. The patient’s condition improved following immunosuppressive therapy.

Five Top Stories in Thyroid Pathology

CONTEXT

Thyroid carcinoma is the most common malignant tumor of endocrine organs, yet it only accounts for approximately 1% of all cancers in the United States with more than 35,000 new cases diagnosed each year and more than 450,000 people living with this disease. While most tumors can be diagnosed without much difficulty, a few tumor types, especially tumors with follicular pattern, sometimes pose a diagnostic challenge.

OBJECTIVE

To discuss morphologic, immunohistochemical, and molecular features of thyroid tumors. We also explore the clinicopathologic features of papillary microcarcinoma and medullary microcarcinoma and how the latter is related and differentiated from C-cell hyperplasia. Finally with the ever-growing list of organ systems involved in immunoglobulin (Ig) G4-related diseases, we discuss the still not completely explored IgG-4-related thyroid disease.

DATA SOURCES

Data were obtained from review of the pertinent peer-reviewed literature and institutional experience.

CONCLUSIONS

Histomorphologic evaluation still remains the gold standard for diagnosis in most cases of thyroid diseases. The application of ancillary studies such as immunohistochemistry and molecular diagnosis, including next-generation sequencing, is becoming more common.

Role of IgG4 serology in identifying common orbital lymphoproliferative disorders

AIM

To explore the role of IgG4 serology in identifying common orbital lymphoproliferative disorders.

METHODS

Eighty-one patients with orbital lymphoproliferative diseases were treated in the Department of Ocular Oncology, Beijing Tongren Hospital, Capital Medical University between September 2010 and December 2012. Serum IgG4 levels were measured in 46 cases of idiopathic orbital inflammatory pseudotumor (IOIP), 17 benign lymphoepithelial lesion (BLEL), 12 cases of orbital mucosa-associated lymphoid tissue (MALT), and 6 cases of diffuse large B-cell lymphoma (DLBL) using immuno-scatter turbidmetry (ISTM).

RESULTS

The frequency of elevated IgG4 levels in patients with IOIP, BLEL, MALT, and DLBL was 30.43% (14/46), 76.47% (13/17), 8.33% (1/12), and 0.00 (0/6), respectively. Among the patients with elevated serum IgG4 levels, all IgG-IOIP patients were male, and 92.31% of the IgG4-BLEL patients were female (12/13). The mean serum IgG4 level of IgG4-IOIP patients was lower than that of individuals with IgG4-BLEL, but the variation in serum IgG4 levels was larger in IgG4-IOIP than IgG4-BLEL patients. Only one case of IgG4-MALT with elevated serum IgG4 levels had a medical history >10y, which was significantly longer than the MALT patients with normal serum IgG4 levels. There was no significant elevation of serum IgG4 levels in patients with DLBL.

CONCLUSION

Detecting serum IgG4 levels plays an important role in the differential diagnosis of orbital lymphoproliferative diseases.

Characteristics, diagnosis and therapeutic strategies for IgG4-related orbital disease

Thanks to detailed studies conducted in recent years, a new disease syndrome was identified in 2001. It is known as a IgG4-related disease and its differentiation is based on the analysis of IgG4 levels in the affected tissues. The IgG4-related disease is considered to be a generalized pathological process involving a wide spectrum of various disorders that may affect distant organs. Orbital IgG4-related disease is a recently reported issue that may prove important for the elucidation of the etiology of idiopathic, lymphoplasmacytic or fibrotic disorders of various organs, including the orbits. In this article, we are describing epidemiology and differential diagnostics of IgG4-related orbital disease with particular focus on pseudotumors, MALT lymphomas and lymphocyte/plasma cell infiltrations of the orbit. We are also discussing therapeutic possibilities currently available in the management of the disease.

[IgG4-related disease]

IgG4-related disease is a recently described clinicopathological entity showing a wide spectrum of clinical manifestations that share a common pathology. Its most characteristic feature is the formation of inflammatory tumors in different organs, which makes differentiation mainly with neoplastic diseases fundamental. The inflammatory process is typically comprised of IgG4 lymphoplasmacytic cells. The pathophysiological role of the immunoglobulin is not clear. The treatment of choice is corticosteroids. This article aims to summarize the main features of the disease.

IgG4-Related Ophthalmic Disease: Pooling of Published Cases and Literature Review

In recent years, IgG4-related ophthalmic disease (IgG4-ROD) has emerged as a common cause of orbital inflammation, accounting for a substantial proportion of idiopathic orbital inflammation and lymphoid hyperplasia. The last pooled analysis of published cases was conducted in 2012, but a large number of new cases have been added to the literature since then. In this review, we present the demographic, clinical, histological, and treatment data for 172 published cases of biopsy-confirmed IgG4-ROD. Results are accompanied by a review of the relevant literature.

Sclerosing mesenteritis mimics gynecologic malignancy

•Sclerosing mesenteritis, and associated inflammatory conditions of the retroperitoneum, may mimic malignancy or infection.•Attempted surgical excision of sclerosing mesenteritis and other retroperitoneal conditions often lead to a morbid and unsuccessful surgery.•These conditions are immune-mediated, and respond remarkably well to immunosuppression.

Rituximab for IgG4-related disease: a prospective, open-label trial

OBJECTIVES

To evaluate the efficacy of rituximab (RTX) in IgG4-related disease (IgG4-RD) in an open-label pilot trial.

METHODS

We treated 30 IgG4-RD patients with two doses of RTX (1000 mg each). The participants were either treated with RTX alone (n = 26; 87%) or required to discontinue baseline glucocorticoids (GC) within 2 months (n = 4; 13%). Disease activity was measured by the IgG4-RD Responder Index (IgG4-RD RI) and physician's global assessment (PGA). Disease response was defined as the improvement of the IgG4-RD RI by two points. The primary outcome, measured at 6 months, was defined as: (1) decline of the IgG4-RD RI ≥2 points compared with baseline; (2) no disease flares before month 6; and (3) no GC use between months 2 and 6. Complete remission was defined as an IgG4-RD RI score of 0 with no GC use.

RESULTS

Disease responses occurred in 97% of participants. The baseline IgG4-RD RI and PGA values, 11±7 and 63±22 mm, respectively, declined to 1±2 and 11±16 mm at 6 months (both p<0.00001). The primary outcome was achieved by 23 participants (77%). Fourteen (47%) were in complete remission at 6 months, and 12 (40%) remained in complete remission at 12  months. Among the 19 with elevated baseline serum IgG4, IgG4 concentrations declined from a mean of 911 mg/dL (range 138-4780 mg/dL) to 422 mg/dL (range 56-2410 mg/dL) at month 6 (p<0.05). However, only 8 (42%) of the 19 achieved normal values.

CONCLUSIONS

RTX appears to be an effective treatment for IgG4-RD, even without concomitant GC therapy.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov identifier: NCT01584388.

Can IgG4 Levels Identify the Ulcerative Colitis Subtype of Inflammatory Bowel Disease?

Background

Pancreatitis and exocrine pancreatic insufficiency may occur as extraintestinal manifestations of inflammatory bowel disease. Recently, autoimmune pancreatitis and colitis have been described as presentations of IgG4-related disease. IgG4+ plasma cells have been identified in colon tissue from patients with refractory forms of inflammatory bowel disease. The presence of elevated serum/tissue levels of IgG4 and the frequency of exocrine pancreatic insufficiency in inflammatory bowel disease are still a source of controversy. Our aim was to investigate the meaning of elevated IgG4 levels in patients with inflammatory bowel disease.

Methods

A cross-sectional study analyzed 56 patients with a diagnosis of inflammatory bowel disease recruited by convenience sampling from two tertiary centers in Midwestern Brazil. All patients underwent fecal pancreatic elastase testing for detection of exocrine pancreatic insufficiency and serum IgG4 measurement. Findings were correlated with clinical and epidemiological data and disease activity.

Results

Elevated serum IgG4 levels were found in 10 patients, and were most frequent in ulcerative colitis (nine cases), with a prevalence ratio of 16.42 (95% CI: 3.32 - 79.58). Ten patients (10 of 56, 17.8%) were diagnosed with exocrine pancreatic insufficiency, which did not correlate with disease activity, and serum IgG4 levels.

Conclusion

Exocrine pancreatic insufficiency is prevalent in patients with inflammatory bowel disease, but it is not associated with elevated serum IgG4 levels. The high prevalence of elevated serum IgG4 in ulcerative colitis suggests that this parameter has potential for use as a diagnostic biomarker.

Sclerosing mediastinitis of unknown origin: Report of a case

•

Sclerosing mediastinitis, also known as fibrosing mediastinitis, is a rare disease.

•

We experienced a case of sclerosing mediastinitis without IgG4-related disease.

•

This case did not fit the criteria for IgG4-related disease, and it was therefore unclear whether steroid therapy should be used for this case.

•

We will continue to carefully follow up this patient’s residual lesion, and there have been no changes in the lesion at present.

Introduction

We herein describe a rare case of a sclerosing mediastinitis without IgG4-related disease. This case was clearly excluded from IgG4-related disease, because this patient’s serum IgG4 level was not elevated. Specifically, this patient’s serum IgG4 level was 7.9 mg/dl (4.8–105).

Presentation of case

A 61-year-old Japanese female presented at our hospital due to an abnormal chest X-ray that showed a growing shadow in the mediastinum. Chest computed tomography (CT) showed an 80 × 75 × 75 mm tumor, which located in the anterior mediastinum. This large tumor surrounded the thoracic aorta, left brachiocephalic vein and superior vena cava. It was difficult to obtain a definitive diagnosis. We tried to perform three biopsies, and eventually performed a partial resection of the tumor.

Discussion

This case did not fit the criteria for IgG4-related disease, and it was therefore unclear whether steroid therapy should be used for this case. We will continue to carefully follow up this patient’s residual lesion, and there have been no changes in the lesion at present.

Conclusion

Sclerosing mediastinitis and IgG4-related disease should be included in the differential diagnosis of patients presenting with a mediastinal tumor. However, sclerosing mediastinitis is difficult to diagnose, and it is important to obtain a sufficient amount of tissue to ensure an accurate diagnosis.

Reactive nodular fibrous pseudotumor involving the gastrointestinal tract and mesentery: A case report and review of the literature

Reactive nodular fibrous pseudotumor (RNFP) is a tumor-like lesion that is characterized by reactive fibroblast/myofibroblast proliferation within collagenic hyalinized stroma, due to its association with injury or inflammation. The current study describes the case of a 60-year-old female with a history of abdominal surgery and abdominal pain. Upon laparoscopy, multiple nodules attached to the outer layer of the colon and mesentery were identified, and therefore, complete surgical excision was performed. Macroscopically, the nodules were well-circumscribed, firm, tan-white in color and ranged in size between 2.0–10.0 cm at the greatest dimension. Microscopically, the nodules were composed of spindle and stellate cells in a dense collagenic hyalinized background with sparse lymphocytic infiltration. Immunohistochemical analysis demonstrated positive staining for vimentin, smooth muscle actin and cluster of differentiation (CD) 117, and focally-positive keratin staining with AE1/AE3; however, no staining was observed for gastrointestinal stromal tumor 1, CD34, S-100, anaplastic lymphoma kinase or β-catenin. Therefore, it was proposed that the lesion may be most accurately described as an RNFP. The current study reports a rare case of RNFP, emphasizing its histopathological features and differential diagnoses to promote an improved and broader understanding of this poorly understood condition.

A case of solely lung-involved IgG4-related disease mimicking tuberculosis

IgG4-related disease (IgG4-RD) is a chronic progressive autoimmune disease. Solely lung involved IgG4-RD is extremely rare. Herein, we reported a case of IgG4-related disease as mimicking tuberculosis. A 52-year-old male patient was admitted due to cough and hemoptysis for two months and fever for 1 month. The pre-admission diagnosis in another hospital was secondary pulmonary tuberculosis, but the quadruple anti-tuberculosis therapy was ineffective and the disease condition continued to deteriorate. The percutaneous lung biopsy was carried out after admission and the pathological diagnosis was IgG4-related disease. The patient's disease condition was improved following hormonal therapy.

The diagnostic utility of serum IgG4 concentrations in IgG4-related disease

OBJECTIVES

We evaluated the sensitivity, specificity and positive and negative predictive values of elevated serum IgG4 concentrations for the diagnosis of IgG4-RD.

METHODS

Between 2001 and 2011, 190 unique patients had elevated serum IgG4 measurements. We reviewed electronic medical records to determine the indication for IgG4 measurement and underlying clinical diagnosis. Additionally, we reviewed the records of 190 other randomly selected patients from a pool of 3360 with normal results, to evaluate test characteristics of the IgG4 measurement.

RESULTS

Among 380 patients analysed, 72 had either probable or definite IgG4-RD. Sixty-five of the 72 IgG4-RD patients had elevated serum IgG4 concentrations (mean: 405 mg/dL; range 140-2000 mg/dL), for a sensitivity of 90%. Among the 308 subjects without IgG4-RD, 125 had elevated IgG4 (mean: 234 mg/dL; range 135-1180 mg/dL) and 183 had normal IgG4 concentrations, for a specificity of 60%. The negative predictive value of a serum IgG4 assay was 96%, but the positive predictive value only 34%. Analysis of the serum IgG4/total IgG ratio did not improve these test characteristics. Doubling the cutoff for IgG4 improved specificity (91%) but decreased sensitivity to 35%.

DISCUSSION

Multiple non-IgG4-RD conditions are associated with elevated serum IgG4, leading to poor specificity and low positive predictive value for this test. A substantial subset of patients with biopsy-proven IgG4-RD do not have elevated serum IgG4. Neither doubling the cutoff for serum IgG4 nor examining the serum IgG4/IgG ratio improves the overall test characteristics for the diagnosis of IgG4-RD.

Plasmablasts as a biomarker for IgG4-related disease, independent of serum IgG4 concentrations

OBJECTIVES

We examined the utility of circulating total and IgG4+ plasmablasts as biomarkers of diagnosis and disease activity in IgG4-related disease (IgG4-RD).

MATERIALS METHODS

We evaluated patients with active, untreated, biopsy-proven IgG4-RD affecting various organs. Flow cytometry was used to measure total plasmablast and IgG4+ plasmablast counts by gating peripheral blood for CD19lowCD38+CD20-CD27+ cells and CD19lowCD38+CD20-CD27+IgG4+ cells. Serum IgG4 concentrations were measured by nephelometry. We compared 37 IgG4-RD patients to 35 controls, including healthy individuals (n=14) and patients with other inflammatory diseases before treatment (n=21).

RESULTS

The IgG4-RD patients' mean age was 59, and 68% were male. Fourteen patients (38%) had three or more organs involved. The IgG4-RD patients had substantially elevated total plasmablast counts (median 4698/mL, range 610-79524/mL) compared to both untreated disease controls (median 592/mL, range 19-4294/mL; p < 0.001) and healthy controls (median 94/mL, range 1-653/mL; p < 0.001). Thirteen IgG4-RD patients (36%) had normal serum IgG4 concentrations (mean 60 mg/dL, range 5-123 mg/dL, normal <135 mg/dL). However, the median plasmablast count was not significantly lower in that subset with normal serum IgG4 concentrations (3784/mL) compared to those with elevated serum IgG4 (5155/mL) (p = 0.242). Among the 12 rituximab (RTX)-treated patients, the median plasmablast level during disease flare was 6356/mL (range 1123-41589/mL), declining to 1419/mL (range 386/mL-4150/mL) during remission (p < 0.01).

CONCLUSIONS

Circulating plasmablasts are elevated in active IgG4-RD, even in patients with normal serum IgG4 concentrations. Plasmablast counts are a potentially useful biomarker for diagnosis, assessing response to treatment, and determining the appropriate time for re-treatment.

Eosinophilic angiocentric fibrosis of the nose and sinuses

BACKGROUND

Eosinophilic angiocentric fibrosis is a rare benign disorder of the upper respiratory tract. It is slow growing and progressive, with characteristic histological appearances.

METHODS

We report the largest single-institution case series of sinonasal eosinophilic angiocentric fibrosis to date, comprising nine patients. The current literature is reviewed, showing emerging evidence that this condition may belong to the immunoglobulin G4-related disease spectrum.

RESULTS

The series comprised five female and four male patients, with a mean age at presentation of 53 years. All were treated surgically. Six patients had no signs of recurrent disease after an average of 8.5 years. One patient went on to develop granulomatosis with polyangiitis (Wegener's granulomatosis), which required immunosuppressive therapy.

CONCLUSION

The first-line management of this rare condition is complete surgical excision. Chronic granulomatous conditions, including granulomatosis with polyangiitis, should be excluded before a diagnosis is made, and patients should be carefully followed.

IgG4-related orbital inflammation presenting as unilateral pseudotumor

IgG4 related systemic disease (IgG4-RSD) has been recognised in the last few years. Orbital pseudotumor as a presentation of IgG4-RSD is one of the rare complaints encountered in pediatric population. It is an inflammatory condition of unknown etiology characterized by tumorous swelling of the organs, characteristic histopathologic changes and elevated IgG4: IgG plasma cells ratio. The disease is also characterized by involvement of varied organ systems. The authors describe a seven-year-old boy with orbital pseudotumor after two years of initial onset with waxing and waning course, steroid responsive lesion and biopsy suggestive of IgG4-RSD involving the extraocular soft tissue. Treatment with oral corticosteroids and Azathioprine produced a significant decline in the pseudotumor size. It is important for pediatricians to be aware of this condition as appropriate recognition and management is important to prevent long-term damage of the tissue involved. This is the first case of IgG4 related orbital pseudotumor reported from India.

Autoimmune pancreatitis: updated concepts of a challenging diagnosis

Autoimmune pancreatitis is a benign process characterized by inflammation and fibrosis. It is now known that cases of "autoimmune pancreatitis" actually consist of two distinct pathologic entities. Type 1 autoimmune pancreatitis is a manifestation of a systemic process, immunoglobulin G subclass 4 (IgG4)-related disease. IgG4-related disease can affect virtually every organ system in the body. Type 1 affects older patients and is characterized by an elevated serum IgG4 level and sites of extrapancreatic disease. Type 2 autoimmune pancreatitis is a disease process confined to the pancreas. It affects younger patients and is associated with inflammatory bowel disease. Type 2 is not associated with elevated IgG4 levels or extrapancreatic disease. Both subtypes can mimic malignancy, particularly pancreatic cancer. Awareness of the clinical and imaging features of the subtypes of autoimmune pancreatitis is important to avoid an incorrect diagnosis of malignancy.

The clinical spectrum of IgG4-related disease

IgG4-related disease (IgG4-RD) is an emerging immune-mediated disease with the capability of involving essentially any organ. The epidemiology of this disease has not been explored in detail. A majority of patients reported in the literature to date are from Japan, but the condition has been described all across the world and there is no strong evidence to suggest a predilection for Asian populations. The mean age at diagnosis is approximately 60 years and there is a decided male predominance for many clinical features, with an overall male:female ratio of 8:3. A cardinal feature of IgG4-RD is single or multiple organ swelling that often raises concern for malignancy. IgG4-RD should be suspected in patients presenting with unexplained enlargement or swelling of one or more organs. Presenting features vary substantially according to the specialty to which patients present first; in addition, the disease can be diagnosed unexpectedly in pathological specimens or identified incidentally on radiology studies. Involvement of major organs is common and IgG4-RD may lead to organ failure, particularly in the pancreas, liver and biliary tree, kidneys, thyroid gland, lungs, and aorta. The diagnosis of IgG4-RD relies on the coexistence of various clinical, laboratory and histopathological findings, although none is pathognomonic by itself.

Characterizing IgG4-related disease with ¹⁸F-FDG PET/CT: a prospective cohort study

PURPOSE

IgG4-related disease (IgG4-RD) is an increasingly recognized clinicopathological disorder with immune-mediated inflammatory lesions mimicking malignancies. A cohort study was prospectively designed to investigate the value of (18)F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) in characterizing IgG4-RD.

METHODS

Thirty-five patients diagnosed with IgG4-RD according to the consensus criteria were enrolled with informed consent. All patients underwent baseline (18)F-FDG PET/CT evaluation. Among them, 29 patients underwent a second (18)F-FDG PET/CT scan after 2 to 4 weeks of steroid-based therapy.

RESULTS

All 35 patients were found with (18)F-FDG-avid hypermetabolic lesion(s); 97.1% (34/35) of these patients showed multi-organ involvement. Among the 35 patients, 71.4% (25/35) patients were found with more organ involvement on (18)F-FDG PET/CT than conventional evaluations including physical examination, ultrasonography, and computed tomography (CT). (18)F-FDG PET/CT demonstrated specific image characteristics and pattern of IgG4-RD, including diffusely elevated (18)F-FDG uptake in the pancreas and salivary glands, patchy lesions in the retroperitoneal region and vascular wall, and multi-organ involvement that cannot be interpreted as metastasis. Comprehensive understanding of all involvement aided the biopsy-site selection in seven patients and the recanalization of ureteral obstruction in five patients. After 2 to 4 weeks of steroid-based therapy at 40 mg to 50 mg prednisone per day, 72.4% (21/29) of the patients showed complete remission, whereas the others exhibited > 81.8% decrease in (18)F-FDG uptake.

CONCLUSION

F-FDG PET/CT is a useful tool for assessing organ involvement, monitoring therapeutic response, and guiding interventional treatment of IgG4-RD. The image pattern is suggested to be updated into the consensus diagnostic criteria for IgG4-RD.