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

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.

IgG4-related uveitis. A French cohort and literature review

INTRODUCTION

IgG4-related disease (IgG4-RD) is a fibro-inflammatory disorder that can affect almost any organ. IgG4-related ophthalmic disease is a protean condition involving the orbit and ocular adnexa. Although a few cases of uveitis have been reported, the exact pattern of IgG4-related intraocular manifestations remains unclear. Here, we report on a nationwide French multicenter cohort of patients with IgG4-RD and uveitis and conducted a literature review.

METHODS

Patients with uveitis and a concomitant definite diagnosis of IgG4-RD (Revised Comprehensive Diagnostic criteria, American College of Rheumatology/European League Against Rheumatism classification criteria for IgG4-RD, International Consensus Diagnostic Criteria for auto-immune pancreatitis, or diagnostic criteria for IgG4-related hypophysitis), were screened from our national IgG4-RD and systemic fibrosis database. Concomitantly, we conducted a PubMed literature review and selected cases of definite IgG4-RD with uveitis.

RESULTS

We reported on 16 patients (8 from our database and 8 from the literature) and a total of 30 episodes of uveitis. Uveitis cases represented 3 % of total IgG4-RD patients in the national database on IgG4-RD and systemic fibrosis. Uveitis was inaugural in IgG4-RD in 4/16 cases (25 %) (appearing before any other IgG4-related symptom, at a median of 9 months), occurred concurrently to other IgG4-related symptoms in 9/16 cases (56 %) (at a median of 15 months before IgG4-RD diagnosis), and appeared during follow up in 3/16 patients (19 %) (at a median of 57 months after first IgG4-related symptoms). When uveitis occurred during follow up, it was associated with IgG4-RD manifestations in other organs in 6/9 patients (67 %). Uveitis was bilateral in 8/16 cases (50 %) and granulomatous in 5/10 cases (50 %). It was anterior in 8/13 (62 %), intermediate in 3/13 (23 %), and global (panuveitis) in 4/13 patients (31 %). Median serum IgG4 at diagnosis was 3.2 g/L. Median follow up time was of 6 years, during which 8/16 patients (50 %) experienced at least one relapse of uveitis. Treatment data was available for 29/30 uveitis flares. Steroids were used in 28/29 episodes of uveitis (97 %), leading to remission of uveitis in 16/28 cases (57 %). Methotrexate and rituximab (in combination with systemic steroids) were administered as second- or third-line therapy in 6/29 (21 %) and 5/29 (17 %) episodes of uveitis, respectively, and led to remission of uveitis in 4/6 cases (67 %) and 4/5 cases (80 %), respectively. One third of uveitides required at least two different lines of treatment for remission induction (mainly a combination of both systemic steroids and methotrexate or rituximab).

DISCUSSION AND CONCLUSIONS

Uveitis may be one of the initial symptoms of IgG4-RD, and IgG4-RD should be considered in the diagnostic workup of uveitis. Its early onset in IgG4-RD may help with early diagnosis and treatment of the disease. Steroid monotherapy may be sufficient to treat IgG4-related uveitis, yet relapses were frequent (50 %) and ultimately a third of patients required at least two lines of treatment. Hence, steroid-sparing agents can be considered at early stages of the disease, particularly for patients with a high risk of relapse or steroid-related complications.

Reshaping the Concept of Riedel's Thyroiditis into the Larger Frame of IgG4-Related Disease (Spectrum of IgG4-Related Thyroid Disease)

Recently, Riedel's thyroiditis (RT) was assimilated into the larger spectrum of immunoglobulin IgG4-related disease (IgG4-RD) in addition to a particular frame of IgG4-related thyroid disease (IgG4-RTD), underlying IgG4-RT, IgG4-associated Hashimoto's thyroiditis (and its fibrotic variant), and IgG4-related Graves's disease. Our objective was to overview recent data on RT, particularly IgG4-RD and IgG4-RTD. The case and study- sample analysis (2019-2023) included 293 articles and selected 18 original studies: nine single case reports (N = 9, female/male = 2/1, aged: 34-79 years, 5/9 patients with serum IgG4 available data, 2/5 with high serum IgG4) and four case series (N = 21; 4/5 series provided data on IgG4 profile, 3/21 had serum IgG4 assays, and 2/3 had abnormally high values). IgG4-RD and thyroid findings were analyzed in three cohorts (N = 25). Another two studies (N = 11) specifically addressed IgG4-RTD components. On presentation, the patients may have hypothyroidism, transitory thyrotoxicosis, goiter, long-term history of positive anti-thyroid antibodies, and hypoechoic ultrasound thyroid pattern. The 5-year analysis (N = 66) showed the rate of serum IgG4 evaluation remained low; normal values do not exclude RT. Mandatory histological and immunohistochemistry reports point out a high content of IgG4-carrying plasma cells and IgG4/IgG ratio. Unless clinically evident, histological confirmation provides a prompt indication of starting corticoid therapy since this is the first-line option. Surgery, if feasible, is selective (non-responders to medical therapy, emergency tracheal intervention, and open/core needle biopsy). Current open issues are identifying the role of serum IgG4 assays in patients with IgG4-RD, finding out if all cases of RT are IgG4-mediated, applying IgG4-RTD criteria of differentiation among four entities, and providing an RT/IgG4-RTD guideline from diagnosis to therapy. It remains that the central aim of approaching RT in daily practice is the early index of suspicion in order to select patients referred for further procedures that provide enough histological/immunohistochemistry material to confirm RT and its high IgG4 burden.