[Immunoglobulin G4 (IgG4)-related disease. A review of head and neck manifestations]

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.

Immunoglobulin G4-related disease presenting with hypertrophy and sclerosis of the inferior turbinate

Immunoglobulin G4-related disease (IgG4-RD) is a novel clinical disease entity characterized by elevated serum IgG4 concentration and tumefaction or tissue infiltration by IgG4+ plasma cells.1 We report the case of a 56-year-old man who presented with nasal obstruction for 5 years. Rhinoscopy revealed hypertrophy and sclerosis of the inferior turbinate, whereas computed tomography revealed inflammation of the anterior ethmoid sinus and frontal sinuses. An endoscopic inferior turbinectomy was performed, and IgG4-RD was definitively diagnosed based on the histopathological features of the turbinate tissue. Prednisolone was administered postoperatively. IgG4-RD presenting with hypertrophy and sclerosis of the inferior turbinate is rare. Awareness of IgG4-RD originating in the sinonasal cavity is essential to avoid delayed diagnosis.

Visual impairment in immunoglobulin G4-related disease: A case report

The present study reports on the case of a 50-year-old male with sinusitis, diplopia, secretory otitis media and skin eczema for >14 years. The patient presented with visual impairment in both eyes and subxiphoid pain on admission to the First Affiliated Hospital of China Medical University (Shenyang, China). Orbital CT revealed a slightly thickened left inferior rectus muscle. Due to a periocular mass, enlarged lymph nodes, elevated serum immunoglobulin G4 (IgG4) levels and enriched IgG4-positive plasma cells in the lymph nodes, the diagnosis of IgG4-related disease (IgG4-RD), possibly involving at least 10 organs, was established. Following treatment with methylprednisolone, the serum IgG4 levels decreased to normal and binocular vision returned to normal. Unlike previously reported cases, the present case exhibited no swollen masses around the optic nerve. The purpose of the present case report was to improve the understanding of IgG4-RD.

Increased IgG4-positive plasma cells in nodular-sclerosing Hodgkin lymphoma: a diagnostic pitfall

AIMS

Despite increasing interest in the recently established immunoglobulin 4-related disease (IgG4-RD), its pathogenesis and aetiology remain largely unclear. Characteristic histopathological features are one of the key elements of diagnosis, including 'storiform' fibrosis, obliterative phlebitis, increased lymphoplasmacytic infiltration and increased levels of IgG4 in serum and tissue. Histopathological features of IgG4-RD are striking but not specific, and can pose a pitfall for surgical pathologists. This paper aims to determine the actual amount of IgG4+ plasma cells in nodular-sclerosing Hodgkin lymphoma (NSHL) and its potential to be misdiagnosed in routine clinical practice.

METHODS AND RESULTS

IgG4+ plasma cells per high-power field (HPF) and the ratio of IgG4+ versus IgG+ plasma cells (IgG4/IgG ratio) in lymph node biopsies of 24 patients with nodular-sclerosing Hodgkin lymphoma (NSHL) were determined using immunohistochemistry and consensus scoring criteria as used for IgG4-RD. Ten lymph node biopsies with reactive follicular hyperplasia were assessed for comparison. Higher numbers of IgG4+ plasma cells (P < 0.001) were observed in NSHL versus follicular hyperplasia (mean 34 versus 8 per HPF) with a mean IgG4/IgG ratio of 0.38 versus 0.18. Five cases (21%) fulfilled the consensus criteria of IgG4-RD, with >50 IgG4+ plasma cells per HPF and an IgG4/IgG ratio of >0.4. The mean count of IgG4+ plasma cells per HPF in NSHL varied greatly (3-88) with increased numbers of IgG4+ plasma cells seen near areas of fibrosclerosis.

CONCLUSIONS

Significantly higher levels of IgG4+ plasma cells are common in NSHL, emphasising the need to exclude Reed-Sternberg cells by morphology and immunohistochemistry in biopsies where IgG4-RD is suspected.

IgG4-related disease: association between chronic rhino-sinusitis and systemic symptoms

PURPOSE

The objective of this study is to analyze the relationship between chronic rhino-sinusitis (CRS) and systemic symptoms in patients with IgG4-related disease (IgG4-RD).

PATIENTS AND METHODS

The patients with IgG4-RD, confirmed by restrict association with clinical and histopathological manifestations between March 2013 and July 2016, were enrolled and followed-up for 1 year at the Tongren Hospital, Capital Medical University. The patients were divided into two groups: the case group included IgG4-RD patients with CRS confirmed by clinical and imaging, while the control group included IgG4-RD patients without CRS confirmed by clinical and imaging. Age, gender, clinical manifestations, the percentage of eosinophils in peripheral blood, sedimentation (ESR), C-reaction protein, serum IgE and IgG4 levels, histopathology, and treatment drugs at the baseline and 1 year of follow-up were compared between the two groups.

RESULTS

A total of 46 cases met the diagnostic criteria for IgG4-RD. A total of 30 patients (65.2%) had IgG4-RD complicated with CRS, and were aged 49.7 ± 13.4 years, with male:female ratio = 2:1. The disease duration in the case group was longer than that in the control group (3.0 versus 0.8, p = 0.009). The ratio of ocular involvement was higher (86.7 versus 60%, p < 0.001), and allergic manifestations including drug allergy, asthma, and allergic skin were more common (56.5 versus 20%, p = 0.004), with a higher percentage of eosinophils in peripheral blood (8.5 versus 3.3%, p = 0.018) and more sensitive to glucocorticoids (6.0 versus 3.5, p = 0.004) than those in the control group.

CONCLUSIONS

CRS in patients with IgG4-RD was closely associated with IgG4-related ocular lesions, which was more prone to allergic manifestations accompanied by raised percentage of eosinophils in peripheral blood. The treatment of patients with IgG4-RD complicated with CRS was more effective than those with IgG4-RD without CRS.

IgG4-related autoimmune diseases: Polymorphous presentation complicates diagnosis and treatment

BACKGROUND

IgG4-associated autoimmune diseases are systemic diseases affecting multiple organs of the body. Autoimmune pancreatitis, with a prevalence of 2.2 per 100,000 people, is one such disease. Because these multi-organ diseases present in highly variable ways, they were long thought just to affect individual organ systems. This only underscores the importance of familiarity with these diseases for routine clinical practice.

METHODS

This review is based on pertinent articles retrieved by a selective search in PubMed, and on the published conclusions of international consensus conferences.

RESULTS

The current scientific understanding of this group of diseases is based largely on case reports and small case series; there have not been any randomized controlled trials (RCTs) to date. Any organ system can be affected, including (for example) the biliary pathways, salivary glands, kidneys, lymph nodes, thyroid gland, and blood vessels. Macroscopically, these diseases cause diffuse organ swelling and the formation of pseudotumorous masses. Histopathologically, they are characterized by a lymphoplasmacytic infiltrate with IgG4-positive plasma cells, which leads via an autoimmune mechanism to the typical histologic findings--storiform fibrosis ("storiform" = whorled, like a straw mat) and obliterative, i.e., vessel-occluding, phlebitis. A mixed Th1 and Th2 immune response seems to play an important role in pathogenesis, while the role of IgG4 antibodies, which are not pathogenic in themselves, is still unclear. Glucocorticoid treatment leads to remission in 98% of cases and is usually continued for 12 months as maintenance therapy. Most patients undergo remission even if untreated. Steroid-resistant disease can be treated with immune modulators.

CONCLUSION

IgG4-associated autoimmune diseases are becoming more common, but adequate, systematically obtained data are now available only from certain Asian countries. Interdisciplinary collaboration is a prerequisite to proper diagnosis and treatment. Treatment algorithms and RCTs are needed to point the way to organ-specific treatment in the future.

Plasma cell granuloma of the oral cavity: a mucosal manifestation of immunoglobulin G4-related disease or a mimic?

The aim of the study was to test the hypothesis that oral plasma cell granuloma may represent a mucosal manifestation of immunoglobulin (Ig)G4-related disease (IgG4-RD) in the oral cavity. The study sample comprised two males and four females, aged 54-79 years (median 62 years). The lesions were localized on gingival/alveolar mucosa (four cases), hard palate, and floor of the mouth, measuring 17-40 mm (median 31 mm). The duration of the lesions ranged from 3 months to several years. Information on IgG4 serum levels was available for two patients, and these were increased to 1.85 and 1.65 g/L, respectively. The follow-up period ranged 11-30 months (median 13 months). None of the lesions recurred, and none of the patients developed any manifestation of IgG4-RD. Microscopically, all cases presented as nodular lesions composed of numerous polyclonal plasma cells admixed with lymphocytes, histiocytes, mast cells, and eosinophils, set within collagenized stroma in variable proportions. Obliterative phlebitis was observed in two cases. The number of IgG4-positive plasma cells ranged between 51 and 142 per HPF (median 114), while the IgG4/IgG ratio values ranged between 0.16 and 0.72 (median 0.44) and were above 0.40 in three cases. Based on international criteria, two cases were diagnosed as definite and one as probable IgG4-RD. Oral plasma cell granuloma is a heterogeneous group of lesions, and a subset may represent a mucosal manifestation of IgG4-RD in the oral cavity.