Riedel's thyroiditis with increased IgG4 plasma cells: evidence for an underlying IgG4-related sclerosing disease?

Idiopathic hyalinizing fibrosclerosis: A systemic steroid-resistant condition distinct from IgG4-related disease

Since the concept of IgG4-related disease (IgG4-RD) was proposed, that diagnosis has been considered in idiopathic fibroinflammatory diseases in various organs, particularly in cases with multi-organ involvement. We have recently encountered three cases of fibrosing disease of uncertain etiology with shared microscopic appearances. Case 1 (56-year-old man) had an irregular mass at the base of mesentery. Case 2 (29-year-old woman) presented with obstructive jaundice due to an ill-defined mass at the hepatic hilum and two lung nodules. Case 3 (53-year-old man) had multiple solid nodules in the mediastinum, peritoneum, retroperitoneum, and mesentery; he also had diffuse irregular narrowing of the intra- and extra-hepatic bile ducts in keeping with sclerosing cholangitis. Serum IgG4 concentrations were not elevated. Biopsies from the nodular lesions showed extensive hyalinizing fibrosis with an only focal lymphoplasmacytic infiltrate. Thick collagenous bundles are arranged in an irregular or partly whorl pattern. Typical storiform fibrosis or obliterative phlebitis was not observed. The number of IgG4-positive plasma cells was <10 cells/high-power field; the ratio of IgG4/IgG-positive plasma cells was <30%. After the histological diagnosis of sclerosing mesenteritis, pulmonary hyalinizing granuloma, and mediastinal fibrosis was made, they were treated with a trial of steroids, but none showed a significant response. In conclusion, a hyalinizing fibrotic condition can occur at various anatomical sites. They have shared microscopic findings, and are steroid-resistant. Although the clinical presentation may mimic IgG4-RD, the two conditions are likely distinct. We would propose a diagnostic term of 'idiopathic hyalinizing fibrosclerosis' for this under-recognized, rare, systemic condition.

Are sonographic characteristics of Hashimoto's thyroiditis related with immunologic parameters? A cross-sectional study

BACKGROUND

The clinical, laboratory, and imaging characteristics of Hashimoto's thyroiditis are widely recognized. However, there is a dearth of information concerning the relationship between these aspects. The primary objective of this study was to investigate the correlation between sonographic features and immunologic parameters in individuals with Hashimoto's thyroiditis.

METHODS

This cross-sectional study enrolled a cohort of 100 consecutive patients diagnosed with Hashimoto's thyroiditis. Ultrasonography was performed to classify thyroid gland characteristics, including parenchymal heterogeneity (mild/moderate-to-high), extent of fibrosis (none-to-mild/moderate-to-high), and volume (atrophic/non-atrophic). As for immunologic parameters, thyroid autoantibodies (TOA; anti-TPO and anti-Tg), along with IG (immunoglobulin) G4 levels and lymphocyte subsets, were assessed.

RESULTS

Of the 100 patients evaluated, 88 were female (88%) and 12 were male (12%). IgG4/IgG ratio and weekly levothyroxine (LT4) dose were significantly higher in the group with moderate-to-high heterogeneity than the group with mild parenchymal heterogeneity (p = 0.043 and p < 0.001, respectively). Compared to the group with none-to-mild fibrosis, the anti-TPO, IgG4, IgG4/IgG ratio and LT4 dose were significantly higher in the moderate-to-high fibrosis group. Anti-TPO and IgG levels were significantly lower in the atrophic thyroid group compared to the non-atrophic thyroid group. Although not reaching statistical significance, the proportion of plasma cells in the moderate/high fibrosis group was higher than in the non-fibrosis/mild fibrosis group. There was a moderate positive correlation between fibrosis with Anti-TPO, and a low positive correlation between anti-Tg, IgG4 levels with IgG4/IgG ratio.

CONCLUSION

TOA, Ig G4 levels and severity of hypothyroidism were associated with ultrasonographic features such as parenchymal heterogeneity and fibrosis in Hashimoto's thyroiditis.

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).

Our Uncommon Experience with 6 Cases of Riedel's Thyroiditis (Woody Thyroiditis)

Riedel's thyroiditis is a rare form of thyroiditis. Estimated prevalence is 1.06/100,000 population and is reported in 0.05% of thyroidectomy specimens. It has 38% association with systemic fibrotic conditions. We retrospectively reviewed 6 cases of Riedel's thyroiditis at a tertiary care centre in south India, from 2011 through 2019 with special emphasis on demography, clinical presentation, workup, management, intraoperative findings, postoperative outcomes and follow up. There were 4 females and 2 males of which we reported a rare presentation in paediatric age group which was probably never reported before. Presenting symptoms included dysphagia and compressive symptoms in neck. 5 out of 6 cases underwent surgical management- 4 total thyroidectomy and 1 hemithyroidectomy. Postoperative complications noted were temporary hypoparathyroidism, unilateral vocal cord palsy and temporary bilateral vocal cord palsy One case was medically managed with oral corticosteroids. There was no evidence of extra cervical fibrosis on follow up in all patients. There was no cause-specific mortality, and the fibrotic process stabilized or resolved in all patients. Riedel's thyroiditis is a fibroinflammatory disorder presenting with compressive symptoms mandating surgical intervention mainly decompression in the form of isthmectomy. However since extensive interventions are associated with complications it is less favoured approach. Long term follow up of these cases are necessary for detecting evidence of extra cervical fibrosis.

Immunoglobulin G4-Related Thyroid Disease: A Single-Center Experience and Literature Review

BACKGROUND

Immunoglobulin G4 (IgG4)-related disease is an entity that can involve the thyroid gland. The spectrum of IgG4-related thyroid disease (IgG4-RTD) includes Hashimoto thyroiditis (HT) and its fibrotic variant, Riedel thyroiditis, as well as Graves' disease. The early diagnosis of IgG4-RTD is important because it is a medically treatable disease, and a delay in the diagnosis might result in unnecessary surgery. We present a case series of IgG4-RTD with a review of the literature.

METHODS

We retrospectively reviewed the clinical presentation and the radiological and pathological findings of patients diagnosed with IgG4-RTD between 2017 and 2021 at a tertiary medical center in Korea. We also conducted a literature review of IgG4-RTD.

RESULTS

Five patients were diagnosed with IgG4-RTD during the study period. The patients' age ranged from 31 to 76 years, and three patients were men. Most patients visited the clinic for a neck mass, and hypoechogenic nodular lesions were observed on neck ultrasonography. Three patients had IgG4 HT, and two patients had IgG4 Riedel thyroiditis. All patients developed hypothyroidism that necessitated L-thyroxine replacement. The diagnosis of IgG4-RTD was confirmed after a pathological examination of the surgical specimen in the first two cases. However, the early diagnosis was possible after a core needle biopsy in three clinically suspected patients.

CONCLUSION

The diagnosis of IgG4-RTD requires clinical suspicion combined with serology and histological analyses using IgG4 immunostaining. The early diagnosis of IgG4-RTD is difficult; thus, biopsy with IgG4 immunostaining and serum IgG4 measurements will help diagnose patients suspected of having IgG4-RTD.

Clinical features and treatment efficacy for IgG4-related thyroiditis

PURPOSE

This study aimed to clarify the clinical features of and evaluate the treatment efficacy for IgG4-related thyroiditis.

METHODS

Fourteen IgG4-related thyroiditis patients and 42 randomly matched IgG4-related disease (IgG4-RD) patients without thyroiditis in a prospective cohort at the Peking Union Medical College Hospital (PUMCH) were enrolled from 2011 to 2019. Patient demographics, clinical characteristics, laboratory parameters and treatment efficacy were analysed.

RESULTS

The prevalence of IgG4-related thyroiditis in our cohort was 2.0%. The average patient age was 42.8 ± 14.9 years, and the male: female ratio was 1:1. Goiter (14, 100.0%), hard thyroid (14, 100.0%) and neck compression (5, 35.7%) were the most prevalent onset symptoms observed. IgG4-related thyroiditis was characterized by asymmetric diffuse thyroid enlargement on ultrasound. Thirteen (92.9%) patients had hypothyroidism, and all patients had significantly elevated circulating thyroid antibodies. Compared with patients without thyroiditis, patients with IgG4-related thyroiditis had less submandibular gland involvement and lacrimal gland involvement and lower serum IgG4 and T-IgE levels (P = 0.019, P = 0.022, P = 0.004, and P = 0.006, respectively) and more single-organ involvement (P = 0.011). After treatment, the symptoms were relieved, while the size of the thyroid gland did not change significantly, and levothyroxine as a supplemental therapy was still needed.

CONCLUSIONS

IgG4-related thyroiditis is a distinct subtype of IgG4-RD characterized by positive circulating thyroid antibodies and a high rate of hypothyroidism. Although compression symptoms could be relieved with treatment, the thyroid size did not change significantly, and the damage to thyroid function was often irreversible.

IgG4 immunohistochemistry in Riedel's thyroiditis and the recommended criteria for diagnosis: A case series and literature review

OBJECTIVE

Riedel's thyroiditis (RT) is a very rare chronic fibrosing thyroiditis that is often associated with multifocal fibrosclerosis. Although the relationship of RT and IgG4-related disease (IgG4-RD) has been suggested, the expression of IgG and IgG4 in thyroid tissues of patients with RT has seldom been studied.

DESIGN

A case series and literature review.

PATIENTS AND MEASUREMENTS

We searched our hospital's pathology database and identified five cases of RT between 2000 and 2019. The expression levels of IgG4 and IgG in thyroid tissues were detected by immunohistochemistry. We also performed a literature search of the electronic databases PubMed/MEDLINE, Web of Science and China National Knowledge Internet (CNKI). Eight papers were included in this study.

RESULTS

According to immunohistochemistry, the numbers of IgG4+ plasma cells per high-power field (HPF) of the five RT patients at our hospital were 80, 8, 50, 10 and 22, and the respective IgG4+/IgG+ ratios were 76%, 80%, 43%, 19% and 28%. In the literature, 15 RT patients with confirmed IgG4 and IgG immunohistochemical findings were identified. Only seven of them fulfilled the IgG4-RD diagnostic criteria in terms of immunohistochemistry (IgG4+ > 10/HPF, IgG4+/IgG+ > 40%). In order to ensure that most RT cases can meet the IgG4 immunohistochemical criteria, an organ-specific cut-off value (≥10 IgG4+ plasma cells/HPF and ≥ an IgG4+/IgG ratio of 20%) was finally selected in our study.

CONCLUSION

Our findings of IgG4 expression in patients with RT suggest that a cut-off of 10 IgG4+ plasma cells/HPF and an IgG4+/IgG ratio of 20% are more suitable diagnostic criteria for RT in IgG4-RD.

Proposal of diagnostic criteria for IgG4-related thyroid disease

Patients with IgG4-related disease (IgG4-RD) are diagnosed in Japan by comprehensive or organ-specific diagnostic criteria. To date, organ-specific criteria have been established for several organs, but not for the thyroid. We attempted to establish diagnostic criteria for IgG4-related thyroid disease (IgG4-RTD) based on IgG4-RD research by The Research Program on Intractable Diseases from the Ministry of Health, Labour and Welfare of Japan. These criteria have been publicly reported to members of both the Japan Endocrine Society and the Japan Thyroid Association. Thyroid diseases associated with IgG4 include Hashimoto's thyroiditis, Graves' disease and Riedel's thyroiditis. As a comprehensive definition that includes both systematic and organ-specific forms, we use the broad term 'IgG4-related thyroid disease'. Diagnostic criteria for IgG4-RTD comprise the following five items: I) enlargement of the thyroid, II) hypoechoic lesions in the thyroid by ultrasonography, III) elevated serum IgG4 levels, IV) histopathological findings in the thyroid lesion (IgG4⁺ plasma cells >20/HPF and IgG4⁺/IgG⁺ plasma cell ratio >30%) and V) involvement of other organs. "Definitive" diagnosis of IgG4-RTD is made when I, II, III and IV are all fulfilled, while "probable" diagnosis of IgG4-RTD is when I, II, and IV or V are fulfilled. Patients who fulfill I, II and III criteria are considered as "possible" IgG4-RTD. We believe that the proposed diagnostic criteria contribute to more accurate diagnosis of IgG4-RTD as well as exclusion of mimicry. Furthermore, they may lead to better understanding of the clinical implications and underlying pathogenesis of IgG4-RTD.

Riedel Thyroiditis

CONTEXT

Riedel thyroiditis (RT) is a rare inflammatory autoimmune disease that is often a clinically diagnostic dilemma because of its insidious presentation and nonspecific symptoms.

OBJECTIVE

The aim of the present systematic review and meta-analysis is to clarify the presentation, management, and outcomes of RT.

STUDY SELECTION

A systematic search of PubMed/MEDLINE and Web of Science was conducted to identify relevant reports published up to September 2019.

DATA EXTRACTION

First author, country, patient sex, ethnicity, presentation, biochemical status, duration of symptoms, histology, treatment, follow-up duration, and short- and long-term outcomes.

DATA SYNTHESIS

Data from 212 RT patients were retrieved. The mean age was 47 years with a predominantly female population (81%). Neck swelling (89%), dyspnea (50%), and neck pain (41%) were the most common presenting symptoms. Inflammatory markers were elevated in 70% to 97% and thyroid antibody positivity was present in less than 50%. Up to 82% underwent surgical intervention, with the most common being total thyroidectomy in 34% of individuals. Glucocorticoids were used in 70% of individuals with median duration 3 months. Prognosis was reasonable with 90% having resolution or improvement of symptoms.

CONCLUSIONS

This analysis is the largest and most comprehensive to date of RT and provides clinicians with vital information on the common presentation features that may alert to the diagnosis and highlight management options.

IgG4-positive plasma cells in Hashimoto thyroiditis: IgG4-related disease or inflammation-related IgG4-positivity?

Despite the interest of researchers in IgG4-related disease (IgG4-RD), many questions still remain unanswered regarding the thyroid gland. We aimed to clarify the relationship between IgG4-positive plasma cells and the histopathological pattern in the Hashimoto thyroiditis (HT) in a Finnish series. HT specimens (n = 280) were retrieved from the Department of Pathology, Fimlab Laboratories. After re-evaluation, 82 (29%) cases (72 females and 10 males, 52 ± 17 years) with significant fibrosis were selected. CD38, IgG and IgG4 positivity in plasma cells was evaluated by immunohistochemistry. Adjusted IgG4-positive plasma cells per HPF > 20 and IgG4- to IgG-positive plasma cell ratio > 30% were adopted as threshold criteria and related to other morphological features. IgG4-positive HT group included 13 cases (15% from fibrotic HT, 4.6% from all HT, 50 ± 15 years, 11 females) with adjusted HPF count 30 ± 5 (23-40) IgG4-positive cells. IgG4-positivity significantly correlated with the presence of lobulation, oncocytic metaplasia and certain type of fibrosis, fibrosis spread outside the gland, lymphocytes/plasma cells epithelial penetration, the predominance of microfollicles and follicular atrophy in the present study. Despite the persisting uncertainty whether HT is IgG4-RD, HT with IgG4-positive plasma cells is histopathologically distinct entity with some geographic variability.

Hashimoto's Thyroiditis with Increased IgG4-Positive Plasma Cells: Using Thyroid-Specific Diagnostic Criteria May Identify Early Phase IgG4 Thyroiditis

Background: A subset of Hashimoto's thyroiditis (HT), reported as immunoglobulin G4 (IgG4) thyroiditis, is characterized by IgG4+ plasma cell-rich inflammation and marked sclerotic changes, which suggests a close relationship with immunoglobulin G4-related disease (IgG4-RD). However, to date, there is no consensus regarding the cutoff values used to define a significant IgG4+ plasma cell count in thyroid inflammation. We, therefore, sought to validate both the cutoff value of the comprehensive diagnostic criteria (CVC) and the cutoff value of thyroid-specific diagnostic criteria (CVT) for diagnosing IgG4 thyroiditis. Methods: One hundred twenty cases of HT were retrospectively reviewed. According to the CVC (IgG4+ plasma cells >10/HPF (high-power field) and IgG4+/IgG+ plasma cell ratio >40%) and the CVT (IgG4+ plasma cells >20/HPF and IgG4+/IgG+ plasma cell ratio >30%), cases were subclassified as IgG4 thyroiditis or non-IgG4 thyroiditis. Clinical, serological, sonographic, and histopathological characteristics of the two subsets, and the cases diagnosed as IgG4 thyroiditis using different thresholds were compared. Results: Both the CVC and CVT identified the same set of distinct clinical, laboratory, and sonographic features of the cases diagnosed as IgG4 thyroiditis. All 120 cases of HT were able to be divided into four distinct groups. Group A included the 25 cases who were assigned as IgG4 thyroiditis by both the CVC and CVT, whereas Group D included the 85 cases who did not meet either of the cutoff values. Group B and Group C comprised the borderline cases who only met one of the two thresholds. Based on histological evaluation, the cases in Group B who met the CVT demonstrated similar histological features of IgG4 thyroiditis. Conclusions: Although both of the cutoff values can efficiently distinguish IgG4 thyroiditis from its non-IgG4 counterpart, the thyroid-specific cutoff value (CVT, IgG4+ plasma cells >20/HPF, and IgG4+/IgG+ plasma cell ratio >30%) can better identify borderline cases of HT with more fibrotic changes, which may represent an early phase lesion of IgG4 thyroiditis. We propose a new series of clinical and pathological diagnostic clues for both endocrinologists and pathologists to improve the early recognition of IgG4 thyroiditis.

Comprehensive research on thyroid diseases associated with autoimmunity: autoimmune thyroid diseases, thyroid diseases during immune-checkpoint inhibitors therapy, and immunoglobulin-G4-associated thyroid diseases

Various thyroid diseases are associated with autoimmunity. Major autoimmune thyroid diseases are Graves' disease (GD) and Hashimoto's thyroiditis (HT). Thyrotropin receptor is an autoantigen in GD, and its immunogenicity has been examined. Immune-checkpoint inhibitor (ICI) is recently widely used for treatment of malignant tumors, but cases of thyroid diseases during ICI treatment have been increasing. Thyroid diseases during ICI therapy have been investigated in immunological and clinical aspects, and their Japanese official diagnostic guidelines were established. In addition, serum and tissue immunoglobulin-G4 levels have been examined in association with clinicopathological characteristics in GD, HT, and Riedel's thyroiditis. We review these diseases associated with thyroid autoimmunity and comprehensively discuss their potential application in future research and therapeutic options.

Plasma Cell Granuloma of the Thyroid: Review of an Uncommon Entity

Plasma cell granuloma (PCG) is characterized by proliferation of polyclonal plasma cells with associated fibrosis and is often considered part of the heterogeneous group of inflammatory myofibroblastic tumors (IMTs). The thyroid is rarely affected by PCG. A patient having PCG associated with Hashimoto thyroiditis (HT) prompted our literature search that revealed 18 cases of PCG, 55% (n = 10) of which occurred together with HT. The etiopathogenesis of PCG is unknown and there is no specific treatment except surgical excision for compressive symptoms. This entity has an excellent prognosis with no evidence of recurrence or metastasis. Lesions of the thyroid with infiltrating plasma cells include HT, fibrous variant of HT, plasmacytoma, plasma cell myeloma, Riedel thyroiditis, IgG4 (immunoglobulin G4)-related disease, IMT, and PCG. Inflammatory myofibroblastic tumor has ALK gene rearrangements and is considered a neoplasm as opposed to PCG, which is a reactive polyclonal plasma cell proliferation. We believe IMT and PCG are distinct entities and consensus definitions are required for avoiding confusion in the literature.

IgG4-Related Disease of the Thyroid Gland Requiring Emergent Total Thyroidectomy: A Case Report

IgG4-related disease of the thyroid gland is a recently recognized subtype of thyroiditis, often with rapid progression requiring surgical treatment. It is considered as a spectrum of disease varying from early IgG4-related Hashimoto's thyroiditis (HT) pattern to late fibrosing HT or Riedel's thyroiditis patterns. Here, we report a 47-year-old Malay woman presenting with progressively painless neck swelling over 3 years and subclinical hypothyroidism. Computed tomography (CT) scan revealed diffuse thyroid enlargement (up to 13 cm) with retrosternal extension and without regional lymphadenopathy. Fine needle aspiration of the thyroid showed a limited number of follicular epithelial cell groups with widespread Hurthle cell change and scanty background colloid, but no evidence of lymphocytosis. The cytologic features fell into the category of 'atypia of undetermined significance'. Subsequently, the patient developed hypercapnic respiratory failure secondary to extrinsic upper airway compression by the thyroid mass and underwent emergent total thyroidectomy. Histology of the thyroid showed diffuse dense lymphoplasmacytic infiltrate and fibrosis. Follicular cells exhibited reactive nuclear features and some Hurthle cell change. IgG4+ plasma cells were over 40/high power field while overall IgG4/IgG ratio was above 50%. The overall features suggest the diagnosis of IgG4-related disease of the thyroid gland in the form of IgG4-related HT. Post-surgery, the patient was found to have markedly elevated serum IgG4 concentration but PET/CT did not show significant increased fludeoxyglucose uptake in other areas. Her recovery was complicated by a ventilator-associated pneumonia with empyema, limiting early use of corticosteroids for treatment of IgG4-related disease.

Immunoglobulin G4-related Coronary Periarteritis and Luminal Stenosis in a Patient with a History of Autoimmune Pancreatitis

Immunoglobulin G4 (IgG4)-related disease is a systemic inflammatory disorder that was first described in patients with autoimmune pancreatitis. Although IgG4-related disease is thought to involve the cardiovascular system, case reports describing coronary artery involvement are relatively rare. We describe a patient who was previously diagnosed with autoimmune pancreatitis and found to have coronary periarteritis and luminal narrowing. After the initiation of steroid treatment, the patient's coronary periarteritis and luminal stenosis were both ameliorated with an improvement in the serum IgG4 concentration. The present findings collectively suggest that IgG4-related immuno-inflammation may have a role in the development of coronary periarteritis and luminal atherosclerosis.

Riedel's thyroiditis association with IgG4-related disease

CONTEXT

IgG4-positive (+) plasma cells have been reported in both Riedel's thyroiditis (RT) and Hashimoto's thyroiditis (HT). These cells are the hallmark of IgG4-related disease (IgG4-RD).

OBJECTIVE

We sought to determine whether RT is part of IgG4-RD spectrum.

DESIGN, SETTING AND PATIENTS

This was a case-control study performed at a tertiary medical centre. We included RT cases from the period 1958 to 2008 that had sufficient paraffin-embedded tissue for IgG4 immunostaining. Controls were patients with HT, age and gender matched, with similar pathology criteria.

MAIN OUTCOME MEASURE

The main outcome measures were the intensity of the IgG4 staining and the clinical and histological correlates with IgG4-RD.

RESULTS

Six pairs of RT and HT were analysed. The mean age was 44·7 years. In both groups, 5/6 cases had positive IgG4 staining. The mean number of IgG4 + cells/ HPF, normalized to the degree of inflammation, was 3·2 ± 3·0 SD (RT) vs 0·9 ± 0·7 (HT), P = 0·15, for fibrotic areas and 2·1 ± 2·3 SD vs 1·0 ± 0·8 (P = 0·39) for areas with lymphoid aggregates. We found the number of IgG4 +  cells in RT to be inversely correlated with the duration of disease (P = 0·046). Three RT cases had associated comorbidities from the IgG4-RD spectrum while none of the HT cases had such conditions.

CONCLUSIONS

Riedel's thyroiditis is a component of IgG4-RD with the density of the IgG4 +  lymphocytic infiltrate being time dependent. In this small study, we did not identify differences in IgG4 infiltration between RT and HT, minimizing the utility of this marker in RT diagnosis.

IgG4-related disease: a case report with duration of more than 16 years and review of literature

Introduction

IgG4-related disease was first reported in 2001 and was officially named in 2010. It is now considered as a systemic disease that might affect any organ system. The characteristic pathological changes of IgG4-related disease are extensive infiltration of IgG4-positive plasma cells. IgG4-related disease is a kind of benign lesions, but there has not been well-defined standard treatment so far. Patients usually respond well to corticosteroids. The prognosis of IgG4-related disease is perhaps good as long as early detection and treatment.

Case description

We report one case of IgG4-related disease with a 16-years anamnesis with multi-pseudotumor masses. He was diagnosed with chronic kidney disease with wide interstitial renal fibrosis. And he received glucocorticoids therapy. After 2 month therapy, the serum creatinine, erythrocyte sedimentation rate, and serum IgG4 decreased significantly. The discussion includes presentation, clinical course, diagnosis, and prognosis of IgG4-related disease. The case and discussion highlight the importance of diagnosis and the good prognosis of IgG4-related diseases.

Discussion and evaluation

Our case highlights the importance of diagnosis and the good prognosis of IgG4-related diseases. IgG4-related disease is a systemic fibro-inflammatory immune-mediated disorder and now recognized in almost every major organs. Characteristics of the disease is multiple lymph nodes and the response to glucocorticoids therapy is well. In such case, he had a history of 16 years with multi-pseudotumor masses and misdiagnosed for 16 years, if the doctors were not awareness of higher serum immunoglobulin G4 (IgG4) than normal, the correct diagnosis may be missed or delayed. Consequently, appropriate treatment for IgG4-related disease would also be delayed or not provided and likely result in increased morbidity and mortality.

Conclusions

IgG4-related disease is a systemic fibro-inflammatory immune-mediated disorder and progresses slowly. In the present patient the course of IgG4-related disease appears to be benign. The prognosis of IgG4-related disease depend on early diagnosis and treatment.

Riedel's thyroiditis

This article describes an unusual case of Riedel's thyroiditis and discusses its imagery, pathology, and treatment.

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.

A CASE OF RIEDEL'S THYROIDITIS

Background

Riedel thyroiditis is a rare, chronic inflammatory disease of the thyroid, characterized by a dense fibrosis that replaces normal thyroid parenchyma. In literature descriptions of individual cases of Riedel thyroiditis can be found.

Case report

We present an euthyroid patient with multinodular goiter who was diagnosed with Riedel thyroiditis using pathology. Imaging diagnostic methods (Ultrasonography, X-ray computed tomography, Magnetic resonance imaging, Radionuclide imaging) or various tests of thyroid function cannot confirm the diagnosis of Riedel thyroiditis.

Conclusion

Only level of IgG4 may be helpful for the diagnosis of Riedel thyroiditis, while pathology is used for its definitive confirmation.

Immunoglobulin G4-related diseases in the head and neck: a systematic review

BACKGROUND

Immunoglobulin G4 related disease (IgG4-RD) is a poorly understood chronic inflammatory disorder affecting the middle-aged and elderly that can present to the otolaryngologist. We aim to summarize the current literature regarding the manifestations and management of IgG4-RD in the head and neck.

METHODS

Pubmed and EMBASE were searched using the term relevant search algorithm utilizing keywords such as: IgG4 related disease, head and neck, orbit, salivary glands, sialadenitis, Kuttner, angiocentric eosinophilic fibrosis, submandibular, lacrimal, thyroid, dacryoadenitis, nasal, sinus, and Mikulicz's. Reference lists were searched for identification of relevant studies. Case reports, original research and review articles published in English from 1964 to 2014 whose major topic was IgG4-RD affecting the head and neck were included. Data regarding patient demographics, presentation, histopathology, management and treatment outcomes of IgG4-RD were extracted. Level of evidence was also assessed and data were pooled where possible. Three independent reviewers screened eligible studies; extracted relevant data and discrepancies were resolved by consensus, where applicable. Descriptive and comparative statistics were performed.

RESULTS

Fourty-three articles met our inclusion criteria. IgG4-RD most often presents as a mass lesion in the head and neck region. Common diagnostic features include: (1) elevated serum IgG4 level, (2) marked infiltration of exocrine glands by IgG4-positive plasma cells with fibrosis, and (3) marked improvement with corticosteroid therapy and additional immunosuppressive therapy in corticosteroid refractory cases. Early diagnosis and involvement of rheumatology is important in management.

CONCLUSIONS

IgG4-RD is a challenging non-surgical disease that has multiple manifestations in the head and neck. It must be distinguished from various mimics including malignancy, systemic diseases, and infectious. Otolaryngology-Head and Neck surgeons should be aware of this condition and its management.

Overlapping Morphologic and Immunohistochemical Features of Hashimoto Thyroiditis and IgG4-Related Thyroid Disease

Immunoglobulin G4-related disease (IgG4-RD) is an emerging clinicopathologic entity characterized by both IgG4+ plasma cell infiltration and fibrosis in one or more organs, prototypically pancreas or salivary/lacrimal glands. IgG4-RD in the thyroid (IgG4-RTD) is an area of active study, and the relationship between IgG4-RTD and Hashimoto thyroiditis is not fully delineated due to their overlapping histologic features. Retrospective review was performed of all thyroidectomy cases demonstrating lymphocytic inflammation at a single institution over a 4-year period. Approximately half (23/38) of patients had a clinical diagnosis of Hashimoto thyroiditis (HT). Nine of the 38 patients had increased absolute and relative numbers of IgG4+ plasma cells. Patients with a clinical diagnosis of HT had increased lymphoplasmacytic inflammation, but the relative proportion of IgG4+ plasma cells was not increased compared to patients without HT. There was no correlation between IgG4 levels and the amount of fibrosis in patients with or without HT. Patients identified as having the fibrosing variant of HT were not more likely to have increased levels of IgG4+ plasma cells than those without. There is significant morphologic and immunohistochemical overlap between HT and IgG4-RTD. Future studies to identify specific characteristics of IgG4-RTD involving the thyroid are necessary to accurately define this entity.

IgG4-related disease

IgG4-related disease is a protean condition that mimics many malignant, infectious, and inflammatory disorders. This multi-organ immune-mediated condition links many disorders previously regarded as isolated, single-organ diseases without any known underlying systemic condition. It was recognised as a unified entity only 10 years ago. Histopathology is the key to diagnosis. The three central pathology features of IgG4-related disease are lymphoplasmacytic infiltration, storiform fibrosis, and obliterative phlebitis. The extent of fibrosis is an important determinant of responsiveness to immunosuppressive therapies. IgG4-related disease generally responds to glucocorticoids in its inflammatory stage, but recurrent or refractory cases are common. Important mechanistic insights have been derived from studies of patients treated by B-cell depletion. Greater awareness of this disease is needed to ensure earlier diagnoses, which can prevent severe organ damage, disabling tissue fibrosis, and even death. Identification of specific antigens and T-cell clones that drive the disease will be the first steps to elucidate the pathogenesis of IgG4-related disease.

Clinicopathological features of Riedel's thyroiditis associated with IgG4-related disease in Japan

Riedel's thyroiditis (RT) is a rare chronic fibrosing disorder characterized by a hard, infiltrative lesion in the thyroid gland, which is often associated with multifocal fibrosclerosis. Immunoglobulin G4-related disease (IgG4-RD) is typified by infiltration of IgG4-positive plasma cells into multiple organs, resulting in tissue fibrosis and organ dysfunction. In order to evaluate the clinicopathological features of RT and its relationship with IgG4-RD, we performed a Japanese literature search using the keywords "Riedel" and "Riedel's thyroiditis." We used the electronic databases Medline and Igaku Chuo Zasshi, the latter of which is the largest medical literature database in Japan. The diagnosis of RT was based on the presence of a fibroinflammatory process with extension into surrounding tissues. Only 10 patients in Japan fulfilled RT diagnostic criteria during the 25-year period between 1988 and 2012. Two patients with confirmed IgG4/IgG immunohistochemical findings demonstrated 43 and 13 IgG4-positive plasma cells per high-power field, respectively, and the IgG4-positive/IgG-positive plasma cell ratios of 20% and less than 5%. Of the 10 patients with RT, two received glucocorticoids, one of whom experienced marked shrinkage of the thyroid lesion. One patient had extra-thyroid involvement in the form of retroperitoneal fibrosis. Although the clinicopathological features of RT suggest that IgG4-RD may be the underlying condition in some cases, further investigation is needed to clarify the etiology of RT in relation to IgG4-RD.

Fibrosis of the thyroid gland caused by an IgG4-related sclerosing disease: three years of follow-up

Immunoglobulin G4-related sclerosing disease (IgG4-RSD) represents a recently identified inflammatory disorder in which infiltration of IgG4 plasma cells causes fibrosis in organs. While IgG4-RSD is well documented in the pancreas and other organs, it is poorly characterized in the thyroid gland. We report a case of a 48-year-old female with a fibrotic thyroid mass associated with a retroperitoneal fibrosis. Diagnosed early as Riedel disease, the high serum IgG4, immunohistopathology and decreased fibrosis with corticosteroid therapy, finally confirm for the first time, the origin of IgG4-RSD fibrosis of the thyroid.

IgG4-related Hashimoto's thyroiditis--a new variant of a well known disease

Hashimoto's thyroiditis (HT) has been characterized for many years as a well-defined clinicopathologic entity, but is now considered a heterogeneous disease. IgG4-related HT is a new subtype characterized by thyroid inflammation rich in IgG4-positive plasma cells and marked fibrosis. It may be part of the systemic IgG4-related disease. We report a case of a 56-year-old Portuguese man who presented with a one-month history of progressive neck swelling and dysphagia. Laboratory testing revealed increased inflammatory parameters, subclinical hypothyroidism and very high levels of thyroid autoantibodies. Cervical ultrasound (US) demonstrated an enlarged and heterogeneous thyroid gland and two hypoechoic nodules. US-guided fine needle aspiration cytology was consistent with lymphocytic thyroiditis. The patient was submitted to total thyroidectomy and microscopic examination identified typical findings of HT, marked fibrosis limited within the thyroid capsule and lymphoplasmacytic infiltration, with >50 IgG4-positive plasma cells per high-power field and an IgG4/IgG ratio of >40%. After surgery, serum IgG4 concentration was high-normal. Symptoms relief and reduction in laboratory inflammatory parameters were noticed. Thyroid function is controlled with levothyroxine. To our knowledge we report the first case of IgG4-related HT in a non-Asian patient. We also perform a review of the literature regarding IgG4-related disease and IgG4-related HT. Our case highlights this new variant of the well known HT, and helps physicians in recognizing its main clinical features, allowing for proper diagnosis and treatment.

IgG4-related thyroiditis: a case report and review of literature

A 55-year-old male, with a positive medical history for hypothyroidism, treated with stable doses for years was admitted with subacute thyroiditis and a feeling of pain and pressure in the neck. Laboratory tests showed decrease in TSH levels, elevated erythrocyte sedimentation rate, and very high antithyroid antibodies. Owing to enlarging goiter and exacerbation in the patient's complaints, he was operated with excision of a fibrotic and enlarged thyroid lobe. Elevated IgG4 plasma levels and high IgG4/IgG plasma cell ratio on immunohistochemistry led to the diagnosis of IgG4-mediated thyroiditis. We concluded that IgG4-thyroiditis and IgG4-related disease should be considered in all patients with an aggressive form of Hashimoto's thyroiditis.

Increased lymphangiogenesis in Riedel thyroiditis (Immunoglobulin G4-related thyroid disease)

The present study describes in depth a case of Riedel thyroiditis (RT) to clarify its pathogenesis and its putative inclusion in the spectrum of IgG4-related disease. We report the clinicopathological, immunohistochemical, and ultrastructural features of a case of RT in a 39-year-old white Spanish woman, admitted with a hard goiter and cold nodule in the left thyroid lobe. This case represents 0.05 % of a series of 1,973 consecutive thyroidectomies performed in our hospital. More than 80 % of the left thyroid lobe was effaced by fibrosis and inflammation (lymphocytes, 57 IgG4+ plasma cells per 1 high-power field, an IgG4/IgG ratio of 0.67, and eosinophils) with extension into the surrounding tissues and occlusive phlebitis. Immunostaining for podoplanin (D2-40) detected signs of increased lymphangiogenesis in the fibroinflammatory areas that were confirmed by electron microscopy. A strong, diffuse stain for podoplanin and transforming growth factor ß1 was also detected in the same areas. The increased number of lymphatic vessels in RT is reported for the first time. Our findings support the inclusion of RT within the spectrum of IgG4-related thyroid disease (IgG4-RTD). Although the etiology and physiopathology of IgG4-RTD still remain elusive, the results obtained in the present case suggest the participation of lymphatic vessels in the pathogenesis of RT.

Association between serum IgG4 concentrations and the morphology of the aorta in patients who undergo cardiac computed tomography

BACKGROUND

Immunoglobulin G4 (IgG4)-related disease has been suggested to be involved in cardiovascular disorders such as chronic periaortitis. However, it remains unclear whether IgG4-related immuno-inflammation affects the subclinical stages of aortic remodeling. Here, we analyzed the relationship between serum IgG4 concentrations and the morphology of the ascending aorta.

METHODS

Serum concentrations of IgG4 were measured in 322 patients who underwent 320-slice cardiac computed tomography (CT). We assessed the aortic wall area and intravascular area at the portion between the aortic valve and the bifurcation of the pulmonary artery.

RESULTS

In total, 174 patients (54.0%) were diagnosed to have coronary artery disease (CAD) by cardiac CT. The intravascular area was significantly larger in patients with CAD than in those without (893mm(2) vs. 811mm(2), p=0.001). The aortic wall area was slightly, but not significantly, larger in patients with CAD than in those without (183mm(2) vs. 176mm(2), p=0.051). Serum concentrations of IgG4 were significantly higher in patients with an aortic wall area of median or greater size (≥181mm(2)) than in those with a smaller area (<181mm(2)) (32.9mg/dL vs. 23.1mg/dL, p=0.026). In logistic regression analysis using age, gender, and CAD as covariates, the fourth quartile of IgG4 (≥55.4mg/dL) was significantly associated with an aortic wall area of median or greater size with an odds ratio of 2.09.

CONCLUSIONS

Serum concentrations of IgG4 were found to be significantly associated with the aortic wall area. These findings collectively suggest that immuno-inflammatory processes may play a role in the subclinical stages of aortic remodeling.

Serum levels of IgG and IgG4 in Hashimoto thyroiditis

Although IgG4-related disease is characterized by extensive infiltration of IgG4-positive plasma cells and lymphocytes of various organs, the details of this systemic disease are still unclear. We screened serum total IgG levels in the patients with Hashimoto thyroiditis (HT) to illustrate the prevalence of IgG4-related thyroiditis in HT. Twenty-four of 94 patients with HT (25.5%) had elevated serum IgG levels and their serum IgG4 was measured. Five of the 24 cases had more than 135 mg/dL of IgG4, which is the serum criterion of IgG4-related disease. One was a female patient who was initially treated as Graves' disease and rapidly developed a firm goiter and hypothyroidism. The biopsy of her thyroid gland revealed that follicular cells were atrophic with squamous metaplasia, replaced with fibrosis, which was compatible with the fibrous variant of HT. Immunohistochemical examination revealed diffuse infiltration of IgG4-positive plasma cells, and the serum IgG4 level was 179 mg/dL. The levels of IgG and IgG4 were positively correlated with the titers of anti-thyroglobulin antibody or anti-thyroid peroxidase antibody. In conclusion, at least a small portion of patients with HT with high titers of anti-thyroid antibodies may overlap the IgG4-related thyroiditis.

IgG4-related multiorgan disease: report of the first autopsy case

IgG4-related disease (IgG4RD) is a chronic recurring fibro-inflammatory pathology that is considered to be of autoimmune origin. Histopathology is considered to be the gold standard method for diagnosis. IgG4RD affects multiple organs. IgG4RD was first identified in the pancreas and was called autoimmune pancreatitis (AIP). During the following years, the disease spectrum was expanded and it was realised that the extrapancreatic lesions can precede, coexist or appear after the diagnosis of AIP. At present, several illnesses such as Mikulicz disease, Küttner tumour, multifocal fibrosclerosis, etc, are considered to be part of the IgG4RD spectrum. The symptoms of the disease tend to appear over months and years and diagnosis is achieved on average 13.5 months (4-60 months) after the onset. The purpose of this report was to provide information about a case that was sadly fatal but that permitted a complete histopathological study of the damaged tissues.