Distinct clinical, serological, and sonographic characteristics of hashimoto's thyroiditis based with and without IgG4-positive plasma cells

IgG4-Related Hashimoto's Thyroiditis of the Thyroid Gland

Immunoglobulin (Ig) G4-related Hashimoto's thyroiditis is a newly discovered subtype of Hashimoto's thyroiditis and characterized by thyroid inflammation and marked fibrosis. IgG4-related Hashimoto's thyroiditis is very rare and there has been relatively little information available to date. A 46-year-old woman with a past history of thyroid dysfunction visited our outpatient clinic for severe anterior neck swelling. She complained of swallowing discomfort and pain due to severe goiter and was successfully treated with total thyroidectomy. Immunohistochemistry showed thyroid invasion by IgG4-positive cells and an IgG4/IgG ratio over 40%. The patient was diagnosed with IgG4-related Hashimoto's thyroiditis. We report a very rare case of IgG4-related Hashimoto's thyroiditis with severe goiter. A more comprehensive understanding of the IgG4-related Hashimoto's thyroiditis may help physicians to allow proper diagnosis and treatment of patients with severe goiter.

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.

Serum immunoglobulin G4 levels and Graves' disease phenotype

PURPOSE

We investigated, at diagnosis, the relationship between serum immunoglobulin G4 levels and the main characteristics of Graves' disease: hyperthyroidism severity, goiter size, presence of active Graves' ophthalmopathy, antithyroid antibodies status, and titer.

METHODS

This prospective study included 80 newly diagnosed Graves' disease patients. The main parameters measured at diagnosis: thyroid-stimulating hormone, free thyroxine, free triiodothyronine, total triiodothyronine, thyroglobulin, antithyroid peroxidase antibodies, anti-thyroglobulin antibodies, thyroid-stimulating hormone receptor antibodies, immunoglobulin G4.

RESULTS

In Graves' disease patients, serum immunoglobulin G4 levels were higher than in general population (p = 0.028) and higher in men compared to women (p = 0.002). Only one female patient with intense hypoechoic goiter, high anti-thyroglobulin antibody, and antithyroid peroxidase antibody titers had an elevated serum immunoglobulin G4 level at diagnosis. Patients with immunoglobulin G4 levels above the 75th percentile (>237.52 mg/dl, N = 20) were younger at Graves' ophthalmopathy onset (p < 0.001), had higher antithyroid peroxidase antibody (p = 0.01), and anti-thyroglobulin antibody levels (p = 0.006) and required shorter duration of the first methimazole treatment cycle (p = 0.041) than patients with immunoglobulin G4 below the 75th percentile. At diagnosis, patients with immunoglobulin G4 levels above the 90th percentile (>286.28 mg/dl, N = 8) had lower total triiodothyronine values (p = 0.001) than patients with IgG below the 90th percentile. No significant correlations were found between smoking status (p = 0.58), goiter size (p = 0.50), the presence of ophthalmopathy (p = 0.42) or thyroid-stimulating hormone receptor antibody titers (p = 0.45) and the mean value of immunoglobulin G4 levels at diagnosis.

CONCLUSIONS

Our data suggest that Graves' disease patients with elevated immunoglobulin G4 levels at diagnosis have a phenotype characterized by higher anti-thyroglobulin antibody and antithyroid peroxidase antibody titers, less severe T3 hyperthyroidism, younger age at ophthalmopathy onset and require a shorter duration of the first methimazole treatment cycle.

Clinical Features of Patients with Basedow's Disease and High Serum IgG4 Levels

Objective IgG4-related disease is a recently characterized condition presenting with high blood IgG4 levels, swelling of organs, and hypertrophic lesions. This disease is associated with thyroid disease, Hashimoto's disease, and Riedel's thyroiditis. However, there is little information on the association between IgG4-related disease and Basedow's disease. We herein defined the clinical features of patients with Basedow's disease and high IgG4 levels. Methods We compared two groups of patients with Basedow's disease (n=72) who had either normal IgG4 levels (<135 mg/dL; n=67) or high IgG4 levels (≥135 mg/dL; n=5 [6.9%], mean IgG4: 206±116 mg/dL, IgG4/IgG ratio: 10.6%±3.3%). Patients Seventy-two newly diagnosed, untreated patients with Basedow's disease. Results Compared to the normal IgG4 group, patients in the high IgG4 group were predominantly male and showed a significantly higher thyroid low-echo score (1.8±0.4 vs. 1.2±0.5) and eosinophil count (363±354/mm² vs. 136±122/mm²). Five patients had high IgG4 levels: one had a pancreatic lesion, and four had thyroid lesions. Conclusion Patients with Basedow's disease and high IgG4 levels may represent a new subtype of Basedow's disease. Further studies with larger sample sizes are needed.

Recent advances in knowledge regarding the head and neck manifestations of IgG4-related disease

IgG4-related disease (IgG4-RD) is a chronic inflammatory disorder, characterized by elevated serum IgG4 levels as well as abundant infiltration of IgG4-positive plasmacytes and fibrosis in various organs, including the head and neck region. In particular, the salivary glands, orbit, and thyroid are common sites of disease involvement. IgG4-RD is diagnosed based on various clinical, serological, and histopathological findings, none of which are pathognomonic. Hence, various differential diagnoses, which exhibit elevated serum IgG4 levels and infiltration of IgG4-postive cells into tissues, need to be excluded, especially malignant diseases and mimicking disorders. Systemic corticosteroids are generally effective in inducing IgG4-RD remission; however, recurrent or refractory cases are common. In addition, although the pathogenic mechanisms of IgG4-RD remain unclear, an antigen-driven inflammatory condition is believed to be involved. Recent studies have indicated the important pathogenic role of B cell/T cell collaboration and innate immunity in this disease. Nevertheless, additional research and discussions are needed to resolve many remaining questions. In this review, we provide an overview of the recent insights on the history, clinical features, diagnosis, and treatment of IgG4-RD in the head and neck region. Furthermore, we have also addressed the pathogenesis of this disease.

Clinical Update in Aspects of the Management of Autoimmune Thyroid Diseases

Aspects of autoimmune thyroid disease updated in this review include: immunoglobulin G4 (IgG4)-related thyroid disease (Riedel's thyroiditis, fibrosing variant of Hashimoto's thyroiditis, IgG4-related Hashimoto's thyroiditis, and Graves' disease with elevated IgG4 levels); recent epidemiological studies from China and Denmark indicating that excess iodine increases the incidence of Hashimoto's thyroiditis and hypothyroidism; immunomodulatory agents (ipilimumab, pembrolizumab, nivolumab) activate immune response by inhibiting T-cell surface receptors which down-regulate immune response, i.e., cytotoxic T-lymphocyte antigen 4 and programmed cell death protein 1 pathways; alemtuzumab is a humanised monoclonal antibody to CD52 which causes immune depletion and thyroid autoimmune disease especially Graves' hyperthyroidism; small molecule ligand (SML) agonists which activate receptors, SML neutral antagonists, which inhibit receptor activation by agonists, and SML inverse agonists which inhibit receptor activation by agonists and inhibit constitutive agonist independent signaling have been identified. SML antagonism of thyroid-stimulating hormone-receptor stimulatory antibody could treat Graves' hyperthyroidism and Graves' ophthalmopathy; and thyroxine treatment of subclinical hypothyroidism can produce iatrogenic subclinical hyperthyroidism with the risk of atrial fibrillation and osteoporosis. The increased risk of harm from subclinical hyperthyroidism may be stronger than the potential benefit from treatment of subclinical hypothyroidism.

Immunoglobulin G4-Related Thyroid Diseases

Immunoglobulin G4-related disease (IgG4-RD) is a new disease category involving many organ systems, including the endocrine system in general and the thyroid in particular. Since an initial association was made between hypothyroidism and autoimmune (IgG4-related) pancreatitis, more forms of IgG4-related thyroid disease (IgG4-RTD) have been recognized. Four subcategories of IgG4-RTD have so far been identified: Riedel thyroiditis (RT), fibrosing variant of Hashimoto thyroiditis (FVHT), IgG4-related Hashimoto thyroiditis, and Graves disease with elevated IgG4 levels. Although a male predominance is seen for IgG4-RD in general, RT and FVHT have a female preponderance. The pathogenesis of IgG4-RD is not completely understood; however, genetic factors, antigen-antibody reactions, and an allergic phenomenon have been described. Diagnosis of IgG4-RD requires a combination of clinical features, serological evidence, and histological features. Histology is the mainstay of diagnosis, with IgG4 immunostaining. Although serum IgG4 levels are usually elevated in IgG4-RD, raised serum IgG4 is neither necessary nor adequate for diagnosis. Imaging supports the diagnosis and is a useful tool in disease monitoring. Management of IgG4-RTD is both medical and surgical. Steroids are the first-line treatment and may produce a swift response. Tamoxifen and rituximab are second-line agents used in steroid-resistant patients. Surgical debulking is carried out in RT solely as a procedure to relieve obstruction. Other endocrine associations described with IgG4-RD are hypophysitis and Hashimoto encephalopathy. IgG4-RTD is an uncommon disease entity, and prompt diagnosis and treatment can improve outcomes.

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.

Current Concept of IgG4-Related Disease

IgG4-related disease (IgG4-RD) is a fibroinflammatory disease of unknown etiology, which is characterized by a tendency to form tumefactive lesions, increased serum levels of IgG4, and massive infiltration of IgG4-positive plasma cells with storiform fibrosis and/or obliterative phlebitis. Patients with IgG4-RD have frequently multiorgan involvements such as the pancreas, biliary tree, salivary glands, periorbital tissues, kidneys, lungs, lymph nodes, and retroperitoneum. IgG4-RD mainly affects middle-aged to elderly men except for involvement in lachrymal and salivary glands, so-called Mikulicz's disease. The clinical manifestations of IgG4-RD depend on individually involved organs and respond well to steroid, but the prognosis still remains unclear. Some patients develop serious complications such as obstructive jaundice due to hepatic, gallbladder, or pancreatic lesions; hydronephrosis due to retroperitoneal fibrosis; or respiratory symptoms due to pulmonary lesions. Nomenclatures of individual organ manifestation of IgG4-RD have been internationally consented.

Association between the clinical classification of hypothyroidism and reduced TSH in LT4 supplemental replacement treatment for pregnancy in China

The study was aimed to evaluate the effects of levothyroxine (LT4) supplemental replacement treatment for pregnancy and analyze the associations between the clinical classification of hypothyroidism and reduced thyroid-stimulating hormone (TSH) in LT4 therapy. Totally, 195 pregnant women with hypothyroidism receiving routine prenatal care were enrolled. They were categorized into three groups: overt hypothyroidism (OH), subclinical hypothyroidism (SCH) with negative thyroperoxidase antibody (TPOAb), and SCH with positive TPOAb. The association between the clinical classification and reduced TSH in LT4 supplemental replacement treatment was assessed. The results indicated that reduced TSH was significantly different among the groups according to the clinical classifications (p = 0.043). The result was also significantly different between patients with OH and patients with SCH and negative TPOAb (p = 0.036). Similar result was reported for the comparison between patients with OH and patients with SCH and positive TPOAb (p = 0.016). Multiple variable analyses showed that LT4 supplementation, gestational age and the variable of clinical classifications were associated with reduced TSH independently. Our data suggested that the therapeutic effect of substitutive treatment with LT4 was significantly associated with different clinical classifications of hypothyroidism in pregnancy and the treatment should begin as soon as possible after diagnosis.

Serum Immunoglobulin G4 levels are elevated in patients with Graves' ophthalmopathy

OBJECTIVE

Recent studies have shown close association between serum Immunoglobulin G4 (IgG4) levels and forms of autoimmune thyroiditis. However, there are limited data about the relationship between IgG4 and Graves' ophthalmopathy (GO). In the present study, we aimed to determine the possible association between IgG4 and GO.

DESIGN

Cross-sectional study.

PATIENTS

Sixty-five patients with Graves' disease (GD) and 25 healthy controls were recruited into the study. Thirty-two of these patients had GO.

MEASUREMENTS

Serum IgG4 levels, thyroid functions and thyroid volumes were measured in all participants. Ophthalmological examination including Hertel's exophthalmometer readings (HER), Schirmer's test (ST), 'NO SPECS' classification and clinical activity score evaluation (CAS) were performed to all patients with GD.

RESULTS

IgG4 levels were significantly elevated in patients with Graves' disease compared to controls (P = 0·0001). Also, IgG4 levels were significantly higher in patients with and without GO when compared to control subjects (P = 0·0001 and P = 0·002, respectively). Furthermore, IgG4 levels were significantly higher in the GO group compared with GD patients without GO (P = 0·024). IgG4 levels were observed to increase in parallel to CAS. Compared with other GD patients, 15 GD patients with serum IgG4 levels ≥ 135 mg/dl had higher CAS scores (P = 0·012). None of the factors including, TSH, T3, T4 levels, thyroid volume, HER and ST measurements, affect IgG4 levels as an independent factor.

CONCLUSION

IgG4 levels are evidently increased in patients with GD, and there is a possible relationship between IgG4 and GO. Our results suggest that IgG4 may be helpful in screening GD patients with high risk for GO and may well become a good indicator for the selection of right medication in the future.

The Pathogenesis of Hashimoto's Thyroiditis: Further Developments in our Understanding

Hashimoto's thyroiditis (HT) is part of a spectrum of thyroid autoimmune conditions and this review provides an update on the latest developments in the field. HT has a genetic predisposition with a number of immune-related and thyroid-specific genes conferring disease susceptibility. However, disentangling genes with protective and predisposing effect is a complex process that requires further work. The recent increase in the incidence of HT implicates environmental factors in disease pathogenesis including improved hygiene, increased dietary iodine intake, new treatment modalities and chemical agents. Additional unmodifiable predisposing factors include stress, climate, age and gender. Both cellular and humoral immunity play a role in HT pathogenesis. Defects in T regulatory cells and increased activation of follicular helper T cells may have a role in disease initiation/perpetuation. Infiltrating lymphocytes can be directly cytotoxic to thyroid follicular cells (TFC) or may affect cell viability/function indirectly through cytokine production, which alters TFC integrity and modulates their metabolic and immune function. Thyroid peroxidase and thyroglobulin antibodies are present in the majority of HT patients and help with management decisions. Antibodies against the sodium iodide symporter and pendrin are present in a minority with little known about their clinical relevance. In addition to immune cells, recent work has identified DNA fragments, generated following cell death, and micro RNA as potential factors in HT pathogenesis. Despite the large number of studies, the mechanistic pathways in HT are still not fully understood and further work is required to enhance our knowledge and identify novel preventative and therapeutic clinical targets.

Graves' Disease Patients with Persistent Hyperthyroidism and Diffuse Lymphoplasmacytic Infiltration in the Thyroid Show No Histopathological Compatibility with IgG4-Related Disease

BACKGROUND

IgG4-related disease is a novel disease entity characterized by diffuse lymphoplasmacytic infiltration rich in IgG4-positive plasma cells and fibrosis into multiple organs. There is still controversy over whether some thyroid diseases are actually IgG4-related disease. The objective of this study was to elucidate the clinicopathological features of Graves' disease with diffuse lymphoplasmacytic infiltration in the thyroid.

PATIENTS AND METHODS

Among 1,484 Graves' disease patients who underwent thyroidectomy, we examined their histopathological findings including the degree of lymphoplasmacytic and fibrotic infiltration and levels of IgG4-positive plasma cells in the thyroid. Their clinical pictures were defined by laboratory and ultrasonographic evaluation.

RESULTS

A total of 11 patients (0.74%) showed diffuse lymphoplasmacytic infiltration in the stroma of the thyroid gland. Meanwhile, other patients showed variable lymphoid infiltration ranging from absent to focally dense but no aggregation of plasma cells in the thyroid gland. Based on the diagnostic criteria of IgG4-related disease, 5 of the 11 subjects had specifically increased levels of IgG4-positive plasma cells in the thyroid. Fibrotic infiltration was present in only 1 patient developing hypothyroidism after anti-thyroid drug treatment for 4 years, but not in the other 10 patients with persistent hyperthyroidism. Obliterative phlebitis was not identified in any of the 11 subjects. Thyroid ultrasound examination showed 1 patient developing hypothyroidism who had diffuse hypoechogenicity, but the other hyperthyroid patients had a coarse echo texture.

CONCLUSIONS

In our study, Graves' disease patients with persistent hyperthyroidism who had diffuse lymphoplasmacytic infiltration rich in IgG4-positive plasma cells in the thyroid showed no concomitant fibrosis or obliterative phlebitis.

Diagnostic Approach to the Complexity of IgG4-Related Disease

IgG4-related disease (IgG4-RD) is a systemic disease characterized by the infiltration of IgG4-bearing plasma cells and, more importantly, distinctive histopathological features: storiform fibrosis, obliterative phlebitis, a lymphoplasmacytic infiltrate, and mild-to-moderate tissue eosinophilia. The diagnostic approach is complex and relies on the coexistence of various clinical, laboratory, and histopathological findings, none of which is pathognomonic in and of itself. IgG4-related disease should be suspected in patients presenting with unexplained enlargement or swelling of 1 or more organs or tissue organs. Four laboratory abnormalities often provide initial clues to the diagnosis of IgG4-RD: peripheral eosinophilia, hypergammaglobulinemia, elevated serum IgE levels, and hypocomplementemia. Elevated serum IgG4 levels provided critical information in identifying the first cases of IgG4-RD, but recent studies have reported substantial limitations to the measurement of serum IgG4 concentrations, precluding reliance on serum IgG4 concentrations for diagnostic purposes. In contrast, new studies have suggested a promising role of flow cytometry studies in the diagnosis and longitudinal management of IgG4-RD. Demonstration of the classic histopathological features of IgG4-RD remains crucial to diagnosis in most cases, and biopsy proof is preferred strongly by most disease experts before the initiation of treatment. Of note, the multiorgan nature of IgG4-RD was first established in 2003. This review intends to provide most recent knowledge about the clinical, laboratory, radiological, and pathological characteristics of IgG4-RD that may guide the physician to establish an early diagnosis. We searched PubMed and MEDLINE for relevant articles published between January 1, 2000, and November 1, 2014, using the search terms IgG4 and IgG4-related.

Research Progress on IgG4-Related Hashimoto’s Thyroiditis

IgG4-related disease is a systemic autoimmune disease with unknown cause and involves multiple organs and tissues. This disease became one of research hotspots in the last ten years. IgG4-related Hashimoto’s thyroiditis (HT) exhibits unique clinical pathological characteristics: serum-free thyroxine reduction and increases in thyroid peroxidase antibody and IgG4; massive IgG4-positive plasmocyte infiltration in tissues; significant matrix fibrosis; and severe degeneration of thyroid follicular epithelium. IgG4-related HT is a subtype of HT; it presents relatively good therapeutic effect after thyroxine treatment. Cortical hormones can be used for IgG4 HT patients who may suffer from hypothyroidism with significant thyroid injury during early stage to constrain immune injury. This thesis summarizes clinical and pathological histology of IgG4-related HT based on its characteristics.

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 Systemic Disease Can Be Easily Mistaken as a Uroepithelial Tumor

Immunoglobulin G4-related disease (IgG4-RD) is a newly recognized systemic syndrome characterized by elevated serum IgG4 concentrations and tumefaction or tissue infiltration by IgG4-positive plasma cells. We experienced a case of IgG4-RD involving multiple organs in a 64-year-old female who was referred for a suspected uroepithelial tumor. A mass biopsy confirmed dense lymphoplasmacytic infiltration with an increased number of IgG4-positive plasma cells. We discuss this case and review the literature to bring IgG4-RD to the attention to clinicians because it responds dramatically well to steroid therapy and should be kept in mind as a differential diagnosis to avoid unnecessary surgery.

IgG4 related disease of the head and neck

IgG4 related disease of the head and neck region represents one of the more common manifestations of IgG4 related disease. Involvement of the submandibular and parotid glands, the orbit and thyroid represent some of the more common sites involved by IgG4 related disease. Eosinophilic angiocentric fibrosis, Mikulicz disease and Riedel thyroiditis are also members of the family of IgG4 related disease. Clinically, the disease is characterized by tumefactive lesions, often multicentric, that show a swift response to immunosuppressive therapy. An elevated serum IgG4 represents the only validated blood based biomarker. However, elevated serum IgG4 is detected in only half the patients with this disease. Histology continues to represent the gold standard for the diagnosis of IgG4 related disease: storiform-type fibrosis and obliterative phlebitis constitute characteristic features of this disease. A definitive diagnosis of IgG4 related disease also requires the presence of elevated numbers of IgG4 positive plasma cells as well as an IgG4 to IgG ratio of greater than 40 %. In isolation, elevated numbers of IgG4 positive plasma cells represents a non-specific feature, detected in a variety of other inflammatory as well as neoplastic diseases. Attention to the clinical context, histological features, as well as an elevated IgG4 to IgG ratio is critical to avoiding overdiagnosis 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.

Ultrasonographic appearance of focal Hashimoto's thyroiditis: A single institution experience

The purpose of this study was to determine the ultrasonographic (US) appearance of focal Hashimoto's thyroiditis (FHT). Thirty-seven FHT patients and 60 consecutive patients with 60 papillary thyroid carcinomas (PTC) that were confirmed by cytology or histopathology between January 2011 and December 2013 were analyzed. Using the results of color Doppler imaging, US findings were retrospectively reviewed. Inter-group differences in size, internal content, echogenicity, echo texture, shape, boundary, margin, calcifications, fine echogenic septa, and blood flow were statistically assessed. The US appearances of the FHTs examined were: solid (100%), hypoechoic (97%), heterogeneous (68%), ovoid-to-round shape (73%), well-defined boundary (95%), smooth margin (89%), and hypervascular (46%). Ovoid-to-round shape, well-defined boundary, fine echogenic septa, and hypervascularity were significantly more prevalent for FHTs than for PTCs (p < 0.05). Ovoid-to-round shape and fine echogenic septa have a higher specificity and positive predictive value. FHTs show a spectrum of US appearances, making FHT diagnosis cumbersome. Fine echogenic septa are highly specific for FHT. Ovoid-to-round shape, well-defined boundary and hypervascularity may possibly be associated with FHT.

High Serum IgG4 Concentrations in Patients with Hashimoto's Thyroiditis

Purpose. Since recent reports suggest that Hashimoto thyroiditis (HT) may be associated with IgG4-related disease, we aimed to find out whether the measurement of serum IgG4 allows for the identification of distinct types of HT, with different clinical, sonographic, and serologic characteristics. Methods. The group studied consisted of 53 patients with HT and 28 healthy individuals who underwent thyroid ultrasonography and body composition analysis. Serum concentrations of IgG4, TSH, anti-peroxidase antibodies (TPOAb), anti-TSH receptor antibodies, TNF-α, TGF-β1, Fas Ligand, TRAIL, and chemokines (CXCL9, CXCL11, and CXCL10) were measured by ELISA or radioimmunoassay. Results. The group with IgG4 level >135 IU/ml accounted for 32.5% of the patients. The signs of fibrosis were present in 27.0% of the high-IgG4 patients and in 9.1% of the normal-IgG4 group. The patients with elevated IgG4 required higher doses of L-thyroxine and had significantly lower level of TPOAb (P=0.02) than the non-IgG4-HT individuals and higher TNF-α level in comparison with the controls (P=0.01). Conclusions. Our results suggest that the measurement of serum IgG4 allows for an identification of patients with more rapid progression of HT, requiring higher doses of L-thyroxine. Low TPOAb level and the absence of coexisting autoimmune diseases may suggest distinct pathomechanism of this type of thyroiditis.

Distribution of serum immunoglobulin G4 levels in Hashimoto's thyroiditis and clinical features of Hashimoto's thyroiditis with elevated serum immunoglobulin G4 levels

Immunoglobulin G4-related disease (IgG4-RD) is characterized by elevated serum IgG4 levels, IgG4-positive plasmacytes, and lymphocyte infiltration into multiple organs. IgG4 thyroiditis is a subset of patients with Hashimoto's thyroiditis (HT) who exhibited histopathological features of IgG4-RD; its source of serum IgG4 is suggested to be the thyroid gland. Although a relationship between IgG4-RD and IgG4 thyroiditis has been reported, the meaning of serum IgG4 in HT is uncertain. In this report, we prospectively evaluated serum IgG4 levels and clinical features of patients with HT. A total of 149 patients with HT were prospectively recruited into this study. According to the comprehensive diagnostic criteria of IgG4-RD, patients were divided into two groups: elevated IgG4 (>135 mg/dL) and non-elevated IgG4 (≤135 mg/dL). Median serum IgG4 levels of HT patients were 32.0 mg/dL (interquartile range, 20.0-65.0), with a unimodal non-normal distribution. Six patients (4.0%) had elevated serum IgG4 levels above 135 mg/dL. The elevated IgG4 group was older and exhibited enlarged hypoechoic areas in the thyroid gland, as revealed by ultrasonography, relative to the non-elevated IgG4 group. Levothyroxine (L-T4) replacement doses and titers of anti-thyroid antibodies did not differ significantly between the two groups. Two out of six HT patients with elevated serum IgG4 levels had extra-thyroid organ involvement as seen in IgG4-RD. In conclusion, HT patients with elevated serum IgG4 levels shared clinical features with both IgG4-RD and IgG4 thyroiditis. Longer follow-up periods and histopathological assessments are needed to further understand the meaning of elevated serum IgG4 levels in HT.

Cervical lymph nodes, thyroiditis and ophthalmopathy: the pleomorphic face of an immunoglobulin g4-related disease

We report a case of immunoglobulin G4-related disease (IgG4-RD) presenting with a clinical course suggestive of fibrosing thyroiditis and endocrine ophthalmopathy associated with enlarged cervical lymph nodes. This clinical presentation should prompt a search for associated systemic disorders, including an IgG4-RD. The clue to the exact diagnosis of the underlying disease is histological examination showing an IgG4 plasmatocytic infiltrate in the inflammatory organs involved.

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.

A new type of natural bispecific antibody with potential protective effect in Hashimoto thyroiditis

CONTEXT

As a new antibody concept, natural bispecific antibodies (nBsAbs) have been detected in long-term passive immunization and some diseases, but their potential immunomodulatory role remains unclear. Hashimoto thyroiditis (HT) appears to fulfill the condition for nBsAb production but has not yet been characterized.

OBJECTIVE

The objective of the study was to identify a new nBsAb against thyroid peroxidase (TPO) and thyroglobulin (Tg) in HT patients and to preliminarily explore its immunomodulatory role.

DESIGN, SETTING, AND PATIENTS

Serum samples were obtained from 136 HT patients, 92 diseased controls, and 99 healthy controls for anti-TPO/Tg nBsAb detection. The relationship between anti-TPO/Tg nBsAb and other clinical parameters was also analyzed.

MAIN OUTCOME MEASURES

The anti-TPO/Tg nBsAb was detected using a double-antigen sandwich ELISA. Higher nBsAb levels were found to be associated with decreased inflammation in HT patients.

RESULTS

The prevalence of anti-TPO/Tg nBsAb in HT was 44.9% (61 of 136), significantly higher than that of diseased controls (2.2%, 2 of 92) (P < .0001) and healthy controls (0%, 0 of 99) (P < .0001). HT patients who were nBsAb positive were prone to have significantly lower levels of serum C-reactive protein and TNF-α compared with the nBsAb-negative individuals (P < .05). The serum amyloid A and interferon-γ levels also showed a similar trend in the two groups. The IgG subclass of anti-TPO/Tg nBsAb was IgG4. Further analysis showed a negative correlation between anti-TPO/Tg nBsAb and serum total IgG4 (r = -0.697, P = .025) in IgG4 thyroiditis patients.

CONCLUSIONS

A new type of nBsAb against TPO and Tg in HT patients is identified. Our data also indicate a protective effect of anti-TPO/Tg nBsAb in the pathogenesis of HT and extend prior knowledge about nBsAb in diseases.

Association between idiopathic retroperitoneal fibrosis and autoimmune thyroiditis: a case-control study

BACKGROUND

Idiopathic retroperitoneal fibrosis (IRF) is a rare disease often associated with autoimmune disorders. Whether IRF is associated with Hashimoto's thyroiditis (HT) is poorly understood and only addressed by case-reports. We evaluated the prevalence of HT in a large IRF cohort and in matched controls.

METHODS

We studied 73 consecutive patients with new-onset IRF and 71 controls. The association between HT and IRF was cross-sectionally evaluated in a referral center. Longitudinally, thyroid function tests were also performed. Serum concentrations of FT4, TSH, and anti-thyroperoxidase antibodies (AbTPO) were evaluated together with thyroid ultrasound (US). Lymphocytic infiltrates were characterized in thyroid nodule fine needle aspirates (FNAB). In patients undergoing thyroidectomy, thyroid histology was also reviewed.

RESULTS

A higher prevalence of AbTPO positivity (P<0.03) and US findings suggestive of autoimmune thyroiditis (US-AIT) (P<0.0001) were found in IRF patients compared to controls. In the logistic regression analysis, the risk of AbTPO-diagnosed HT and that of US-AIT was significantly higher in IRF patients than in controls (ORs, 3.56, 95% CI 1.48-8.59, P=0.004 and 4.74, 95% C.I., 2.34-9.61, P<0.0001 in AbTPO-diagnosed HT and US-AIT, respectively). Thyroid histology in IRF patients showed either classical or the fibrous variant of HT. At the end of the follow-up (median, 45 and 36 months in patients and controls, respectively), 25% of IRF patients and 3% of controls were receiving l-thyroxine.

CONCLUSIONS

IRF patients have a higher risk of HT compared to controls. Thyroid function should be monitored in patients with IRF.

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.

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.

IgG4 antibodies in autoimmune polyglandular disease and IgG4-related endocrinopathies: pathophysiology and clinical characteristics

PURPOSE OF REVIEW

This review discusses the IgG4-related disease spectrum (IgG4-RD), the autoimmune polyglandular syndromes (APS), the association of IgG4 with APS, and possible pathobiology.

RECENT FINDINGS

IgG4-RD is a multiorgan autoimmune disorder characterized by fibrous inflammation, IgG4-positive plasma cell infiltration in affected tissues, and elevated serum concentrations of IgG4. IgG4-RD can affect any organ and has a heterogeneous presentation. Consensus criteria for diagnosis in specific organs have been established. The recognition and diagnosis of IgG4-RD are crucial because the disease responds favorably to immunosuppression (e.g., glucocorticoids, rituximab). The precise mechanisms leading to disease are unknown, but IgG4 antibodies may undergo a half antibody exchange, which renders them incapable of activating the complement pathway.

SUMMARY

Despite significant advances in disease recognition and treatment strategies, the disorder remains poorly understood. The precise role of IgG4, whether it is protective or pathogenic, is still being debated.

Manifestations of immunoglobulin G4 related disease in otolaryngology: case reports and review of the literature

Background:

Immunoglobulin G4 related disease is an inflammatory condition characterised by the presence of fibrotic lesions infiltrated by immunoglobulin G4 positive plasma cells. It can arise from almost any region of the body and it is being increasingly recognised in the head and neck. Regardless of the site of involvement, the histopathological resemblance is remarkable. Dense lymphoplasmacytic infiltration, overabundance of immunoglobulin G4 bearing plasma cells and presence of storiform fibrosis are typical findings.

Case reports:

This paper presents two cases of immunoglobulin G4 related disease in which there was involvement of the orbit, the infraorbital nerve and the infratemporal fossa. Diagnosis was established in both cases by biopsying radiologically abnormal tissue in the infratemporal fossa.

Conclusion:

An awareness of this condition is required to establish the diagnosis and initiate appropriate therapy. Glucocorticoids are the mainstay of initial treatment. The effectiveness of B-lymphocyte depletion with rituximab has also been reported. Correct diagnosis may spare patients from unnecessarily radical surgery.

Elevated serum immunoglobulin G4 levels in patients with Graves' disease and their clinical implications

BACKGROUND

Immunoglobulin G4-related disease (IgG4-RD) is a new clinical entity that affects various organs with increased IgG4 positive plasmacytes and progressive fibrosis. While IgG4-RDs in association with Hashimoto's thyroiditis or Riedel's thyroiditis have been reported, the relationship between IgG4-RD and Graves' disease (GD) is yet unknown. To elucidate the relation of GD to IgG4-RD, serum IgG4 levels and their clinical implications in patients with GD were investigated.

METHODS

In this prospective study, serum IgG4 levels were measured in 109 patients with GD and classified into two groups according to the comprehensive diagnostic criteria of IgG4-RD previously established: (i) GD with elevated-IgG4 levels (≥ 135 mg/dL), and (ii) GD with nonelevated IgG4 (<135 mg/dL).

RESULTS

Seven out of 109 patients with GD (6.4%) had elevated serum IgG4 levels [mean ± standard deviation (range): 175.0 ± 44.5 (136-266) mg/dL] and elevated ratios of IgG4/IgG [12.7 ± 4.5% (7.6%-21.2%)]. The remaining patients with GD had serum IgG4 levels and IgG4/IgG ratios of 39.6 ± 27.6 (3-132) mg/dL and 3.2 ± 2.2% (0.3%-11.5%), respectively. Ages in the elevated IgG4 group were significantly higher than those of the nonelevated IgG4 group: 54.7 ± 6.2 versus 43.4 ± 15.4 years, respectively. Ultrasound examinations revealed that the elevated IgG4 group had significantly increased hypoechogenic areas in the thyroid in comparison to the nonelevated IgG4 group (low echo scoring: 1.66 ± 0.81 vs. 0.61 ± 0.89, respectively). In the correlation analysis, TSAb (rs=0.385, n=42) titers were significantly correlated with se rum IgG4 levels, while they were not significantly different between the two groups. In the elevated IgG4 group, symptoms were controllable with a small dose of antithyroidal drug (ATD; n=4), a combination treatment with ATD and L-T4 (n=1), or L-T4 administration only one year after the first visit (n=2).

CONCLUSIONS

A small portion of GD patients harbored elevated serum IgG4 levels. They were older, had increased hypoechoic areas in the thyroid, and appeared to be responsive or prone to be hypothyroid after ATD treatment. Thus, the present study suggests the presence of a novel subtype of GD. Measuring serum IgG4 levels may help to distinguish this new entity and provide potential therapeutic options for GD.

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.

A classification of Hashimoto's thyroiditis based on immunohistochemistry for IgG4 and IgG

BACKGROUND

Hashimoto's thyroiditis (HT) is a common organ-specific autoimmune disease. Antithyroglobulin antibodies (TgAb) and antithyroperoxidase antibodies (TPOAb), predominantly of the immunoglobulin (Ig) G class, are hallmarks of HT. It has been reported that HT can be divided into IgG4 and non-IgG4 thyroiditis. The aim of our study was to investigate the meaning of this classification.

METHODS

Thyroid sections from 53 Hashimoto's patients with stored serum samples were collected to detect IgG4, IgG, α-smooth muscle actin, and transforming growth factor-β1 expression by immunohistochemical staining. The degree of fibrosis of thyroid parenchyma was qualitatively evaluated by Masson's trichrome. Serum total IgG, IgG4, TPOAb IgG, TgAb IgG, TPOAb IgG4, and TgAb IgG4 were detected by enzyme-linked immunosorbent assays (ELISAs).

RESULTS

Based on immunohistochemistry for IgG4 and IgG, 12 cases of IgG4-positive HT and 41 cases of IgG4-negative HT were identified in our study. The patients in the IgG4-positive HT group were significantly younger than those in the IgG4-negative HT group (p=0.023), and no significant differences were found in sex distribution, disease duration, and distribution of thyroid functional status between these two groups. The degree of fibrosis evaluated by Masson's trichrome and the immunohistochemical expression score of TGF-β1 in the IgG4-positive HT were significantly higher than those in the IgG4-negative HT (p<0.05). No significant differences were found in the levels of serum IgG4, total IgG, or IgG4/IgG ratio. However, TPOAb IgG4 and TgAb IgG4 levels and the ratios of TPOAb IgG4/TPOAb IgG, TgAb IgG4/TgAb IgG, TPOAb IgG4/IgG4, and TgAb IgG4/IgG4 were significantly higher in the IgG4-positive HT group than those in the IgG4-negative HT group respectively (p<0.05).

CONCLUSIONS

Our study indicates that HT can be divided into IgG4-positive and IgG4-negative HT, and this classification might have important clinical implications. The levels of IgG4 binding to specific thyroid antigens might be noninvasive markers to differentiate these two different immunophenotypes.

Hashimoto thyroiditis: clinical and diagnostic criteria

Hashimoto thyroiditis (HT), now considered the most common autoimmune disease, was described over a century ago as a pronounced lymphoid goiter affecting predominantly women. In addition to this classic form, several other clinico-pathologic entities are now included under the term HT: fibrous variant, IgG4-related variant, juvenile form, Hashitoxicosis, and painless thyroiditis (sporadic or post-partum). All forms are characterized pathologically by the infiltration of hematopoietic mononuclear cells, mainly lymphocytes, in the interstitium among the thyroid follicles, although specific features can be recognized in each variant. Thyroid cells undergo atrophy or transform into a bolder type of follicular cell rich in mitochondria called Hürthle cell. Most HT forms ultimately evolve into hypothyroidism, although at presentation patients can be euthyroid or even hyperthyroid. The diagnosis of HT relies on the demonstration of circulating antibodies to thyroid antigens (mainly thyroperoxidase and thyroglobulin) and reduced echogenicity on thyroid sonogram in a patient with proper clinical features. The treatment remains symptomatic and based on the administration of synthetic thyroid hormones to correct the hypothyroidism as needed. Surgery is performed when the goiter is large enough to cause significant compression of the surrounding cervical structures, or when some areas of the thyroid gland mimic the features of a nodule whose cytology cannot be ascertained as benign. HT remains a complex and ever expanding disease of unknown pathogenesis that awaits prevention or novel forms of treatment.

A proposal of a diagnostic algorithm with validation of International Consensus Diagnostic Criteria for autoimmune pancreatitis in a Japanese cohort

BACKGROUND

Among many diagnostic criteria for autoimmune pancreatitis (AIP), the International Consensus Diagnostic Criteria (ICDC) first enabled us to diagnose and compare type 1 and type 2 AIP, which permitted tailoring individual diagnostic algorithms depending on local expertise. We compared them and validated ICDC with special reference to levels 1 and 2, and proposed a diagnostic algorithm for AIP in Japan.

METHODS

The diagnostic sensitivity of 5 major criteria (ICDC, Korean, Japanese-2011, Asian, and HISORt criteria) was compared, using 61 patients with AIP. Fifty six patients with pancreatic cancer served as a control. Pancreas imaging on computed tomography (CT) and endoscopic retrograde pancreatography (ERP) were independently evaluated by 3 pancreatologists (5, 10, and 20 years of career experience) and each diagnostic criterion of ICDC was validated with special reference to levels 1 and 2.

RESULTS

The sensitivities of 5 major criteria were 95.1% (ICDC), 90.2% (Korean), 86.9% (Japanese), 83.6% (Asian), and 83.6% (HISORt) with 100% of specificity in each. In the evaluation of pancreas imaging, diagnostic sensitivities of combination with CT and ERP in segmental/focal type AIP were significantly higher than single imaging (26% in CT (P < 0.01) or 35% in ERP (P < 0.05) vs 63% in CT + ERP), but not significantly different in the diffuse type.

CONCLUSIONS

Of the 5 criteria, ICDC is the most sensitive and useful for diagnosing AIP. We have proposed a diagnostic algorithm with CT for the diffuse type of AIP, and combination with CT + ERP followed by EUS-FNA for the segmental/focal type.

Current concept and diagnosis of IgG4-related disease in the hepato-bilio-pancreatic system

Recently, IgG4-related disease (IgG4-RD) has been recognized as a novel clinical entity with multiorgan involvement and unknown origin, associated with abundant infiltration of IgG4-positive cells. The Japanese research committee, supported by the Ministry of Health, Labor and Welfare of Japan, unified many synonyms for these conditions to the term "IgG4-RD" in 2009. The international symposium on IgG4-RD endorsed the comprehensive nomenclature as IgG4-RD, and proposed the individual nomenclatures for each organ system manifestations in 2011. Although the criteria for diagnosing IgG4-RD have not yet been established, proposals include the international pathological consensus (IPC) and the comprehensive diagnostic criteria (CDC) for IgG4-RD for general use, and several organ-specific criteria for organ-specialized physicians, e.g., the International consensus diagnostic criteria (ICDC) and the revised clinical diagnostic criteria in 2011 by the Japan Pancreas Society (JPS-2011) for type1 AIP; the Clinical Diagnostic Criteria 2012 for IgG4-sclerosing cholangitis (IgG4-SC-2012); the diagnostic criteria for IgG4-positive Mikulicz's disease by the Japanese Society for Sjogren's syndrome; and diagnostic criteria for IgG4-related kidney disease by the Japanese Society of Nephrology. In cases of probable or possible IgG4-RD diagnosed by the CDC, organ-specific diagnostic criteria should be concurrently used according to a diagnosis algorithm for IgG4-RD, with referral to a specialist.

IgG4-related ocular adnexal disease mimicking thyroid-associated orbitopathy

A 72-year-old man presented with bilateral eyelid swelling and redness. An orbital CT scan showed bilateral proptosis, extraocular muscle enlargement and swollen lacrimal glands, mimicking thyroid-associated orbitopathy (TAO) with Hashimoto's thyroiditis (HT). During the patient's clinical course, spontaneous remission of lung consolidation (35 × 26 mm) was seen. A diagnosis of IgG4-related disease (IgG4-RD) was made based on an elevated serum IgG4 level (1,020 mg/dL; normal, 4-108), predominance of IgG4-positive plasma cells (IgG4/IgG: 35/70 in HPF) in the lacrimal glands and typical features of Mikulicz's disease. This report provides a novel description of this unusual disease entity among HT, TAO and IgG4-RD.

IgG4-related disease of the head and neck

IgG4-related disease is an uncommon sclerosing and inflammatory mass-forming disease that may affect a single organ or be systemic. The prototypical example of the disease is type 1 autoimmune pancreatitis. After the pancreatobiliary system, the head and neck is the next most common site for involvement by IgG4-related disease. Here, we describe the clinicopathologic features of the head and neck involvement by this disease process with particular attention to involvement of the major salivary glands, the lacrimal glands and periorbital tissues, the upper aerodigestive tract, the thyroid gland, lymph nodes, the ear, and the skin and soft tissues.

The pathology of IgG4-related disease: critical issues and challenges

IgG4-related disease (IgG4-RD) is a chronic and relapsing disease. The diagnosis of IgG4-RD is based on a combination of features that include clinical, imaging, serologic, histology, and immunohistochemistry. Nonetheless, histopathology has emerged as the gold standard for the diagnosis of IgG4-RD. Guidelines for the pathologic diagnosis of this condition have been published by an international group of experts: a triumvirate of histologic features allows for a confident diagnosis of IgG4-RD to be made in most cases: (1) a dense lymphoplasmacytic infiltrate, (2) storiform-type fibrosis, and (3) obliterative phlebitis. Elevated numbers of IgG4-positive plasma cells are essential for the diagnosis, but this feature is not sufficient in, and of, itself. IgG4-positive plasma cells are also seen in a variety of inflammatory and neoplastic diseases. An elevated IgG4 to IgG ratio, more than 40%, improves the specificity of this stain. A wide range of inflammatory and neoplastic diseases including antineutrophil cytoplasmic antibody (ANCA)-related vasculitis, chronic infections, mesenchymal neoplasms, carcinoma, and lymphoma should be excluded before arriving at a diagnosis of IgG4-RD. This review aims to provide the histopathologist with a set of practical guidelines for the diagnosis of IgG4-RD, and also addresses the many controversies associated with the diagnostic aspects of this disease.

Urethral caruncle: a lesion related to IgG4-associated sclerosing disease?

Aims

Urethral caruncle is a benign, polypoid urethral mass that occurs almost exclusively in postmenopausal women. Despite that these lesions are routinely managed with topical medications or excision, their pathogenesis is not well understood. We investigated the possibilities of autoimmune, viral and inflammatory myofibroblastic proliferations as possible aetiologies.

Methods

In 38 patients with urethral caruncle, we utilised immunohistochemistry for immunoglobulin G (IgG) and IgG4 to assess for a potential autoimmune aetiology. Immunohistochemistry was performed in nine patients for Epstein–Barr virus, BK virus, human herpesvirus 8, human papillomavirus, adenovirus and anaplastic lymphoma kinase.

Results

Four patients (11%) showed infiltrates of ≥50 IgG4-positive plasma cells per high power field, of which all showed an IgG4 to IgG ratio greater than 40%. A statistically significant difference (p<0.01) was detected in the mean number of IgG4-positive cells (14.73 per high power field) compared with control benign urethral specimens (mean, 1.19). One patient with increased counts below this threshold had rheumatoid arthritis; none had documented autoimmune pancreatitis or other known manifestations of systemic IgG4-related sclerosing disease. All lesions showed negative reactions for the viral and inflammatory myofibroblastic markers.

Conclusions

Urethral caruncle is a benign inflammatory and fibrous polypoid urethral mass of unclear aetiology. It appears unrelated to viral infection and lacks the abnormal expression of anaplastic lymphoma kinase protein, as seen in inflammatory myofibroblastic tumours. Increased numbers of IgG4-positive plasma cells in a subset of lesions raise the possibility that some cases may be related to the autoimmune phenomena of IgG4-associated disease.

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

BACKGROUND

Riedel's thyroiditis (RT) is a very rare chronic fibrosing disorder of unknown etiology that is often associated with multifocal fibrosclerosis (MFS). Immunoglobulin (Ig) G4-related sclerosing disease (IgG4-RSD), a new clinico-pathological entity also associated with MFS, is characterized by IgG4+ plasma cell infiltration and fibrosis in one or more organs. Although the association of RT and IgG4-RSD has been suggested, it has seldom been studied or reported. We report a classical case of RT with serological (IgG4 levels) and immunohistochemical (IgG and IgG4) assessment, in search of an underlying IgG4-RSD.

PATIENT

The patient was a 57-year-old woman who underwent a subtotal thyroidectomy for a long-standing goiter with a rapidly enlarging isthmic nodule.

RESULTS

Histopathological examination of the surgical specimen revealed all of the morphological features of RT and IgG4-RSD, including partial fibrosis of the thyroid gland with destruction of the thyroid follicular architecture; obliterative phlebitis; and a mixed infiltrate composed of lymphocytes, eosinophils, and plasma cells. The fibro-inflammatory process extended beyond the thyroid capsule into the surrounding tissues. Immunohistochemical examination revealed approximately 70 IgG4+ plasma cells per high power field (HPF) with an IgG4/IgG ratio of 35%. Although serum levels of IgG4 were normal (20 mg/dL), total IgG levels were slightly elevated (1370 mg/dL). There was no evidence of involvement of other organs at the time of RT diagnosis.

CONCLUSIONS

The morphological similarities between RT and IgG4-RSD suggest that these entities are closely related. Therefore, RT with increased IgG4+ plasma cells, with or without elevated IgG4 serum levels, may represent the first clinical manifestation of an underlying IgG4-RSD. However, due to the rarity of both conditions and the limited specificity and sensitivity of both IgG4 serum levels and IgG/IgG4 immunohistochemistry in the diagnosis of IgG4-RSD, further studies are needed to verify this hypothesis.

Distinct histopathological features of Hashimoto's thyroiditis with respect to IgG4-related disease

A form of Hashimoto's thyroiditis with lymphoplasmacytic sclerosing changes and increased numbers of IgG4-positive plasma cells has recently been reported in the literature. These histopathological features suggest that this subtype of Hashimoto's thyroiditis may be closely related to IgG4-related disease. Therefore, this unique form of IgG4-related Hashimoto's thyroiditis, which is referred to as IgG4 thyroiditis, has its own clinical, serological, and sonographic features that are distinct from those associated with non-IgG4 thyroiditis. IgG4 thyroiditis shares similarities with the well-known fibrous variant of Hashimoto's thyroiditis; however, the detailed histopathological features of IgG4 thyroiditis have not been well established. Based on immunostaining results, 105 patients with Hashimoto's thyroiditis were divided into an IgG4 thyroiditis group (n=28) and a non-IgG4 thyroiditis group (n=77). As in our previous reports, IgG4 thyroiditis was associated with a patient population of a younger age, a lower female-to-male ratio, rapid progression, higher levels of thyroid autoantibodies, subclinical hypothyroidism, and diffuse sonographic echogenicity. Histopathologically, this group revealed severe lymphoplasmacytic infiltration, dense stromal fibrosis, marked follicular cell degeneration, numerous micro-follicles, and notable giant cell/histiocyte infiltration. Importantly, the IgG4-related group did not completely overlap with fibrous variant of Hashimoto's thyroiditis. Four cases (14%) in the IgG4 thyroiditis group presented only mild fibrosis in the stroma, whereas 29 cases (38%) in the non-IgG4 thyroiditis group met the diagnostic criteria for fibrous variant of Hashimoto's thyroiditis. Furthermore, we observed three patterns of stromal fibrosis in Hashimoto's thyroiditis: interfollicular fibrosis, interlobular fibrosis, and scar fibrosis. The IgG4 thyroiditis group was significantly associated with the presence of predominant interfollicular fibrosis. In conclusion, IgG4 Hashimoto's thyroiditis presents histopathological features quite distinct from its non-IgG4 counterpart.

Locally destructive skull base lesion: IgG4-related sclerosing disease

A unique case of IgG4⁺ sclerosing disease was diagnosed in the sphenoid sinus, a previously unreported location, and was treated in a novel manner. This study describes the clinical presentation and management of IgG4 sclerosing disease in the paranasal sinuses. A retrospective case review and review of the medical literature were performed. A 38-year-old woman with a 2-year history of constant frontal headaches presented to our clinic. Imaging showed bony destruction of the sphenoid sinus and sellar floor. The patient underwent a right-sided sphenoidotomy with debridement and biopsy. Pathological evaluation showed a dense plasmacytic infiltrate with >150 IgG4⁺ cells/high-power field. She was subsequently started on a nasal corticosteroid with improved patency of the sphenoid antrostomy. We report an unusual case of a middle-aged woman who presented with IgG4-sclerosing disease (IGSD) isolated to the sphenoid sinus. Although our knowledge concerning treatment in extrapancreatic organs is lacking, there is evidence that glucocorticoid treatment improves nasal sinus opacification on CT findings (Sato Y, Ohshima K, Ichimura K, et al., Ocular adnexal IgG4-related disease has uniform clinicopathology, Pathol Int 58:465–470, 2008). This case study and literature review adds to the growing literature describing IGSD in the head and neck and more specifically isolated to the sphenoid sinus with preliminary data concerning local control with topical steroids.

Hashimoto thyroiditis: a century later

More than a century has passed since the first description of Hashimoto thyroiditis (HT) as a clinicopathologic entity. HT is an autoimmune disease in which a breakdown of immune tolerance is caused by interplay of a variety of immunologic, genetic, and environmental factors. Thyrocyte injury resulting from environmental factors results in expression of new or hidden epitopes that leads to proliferation of autoreactive T and B cells. Infiltration of thyroid by these cells results in HT. In addition to the usual type of HT, several variants such as the fibrous type and Riedal thyroiditis are also recognized. The most recently recognized variant is immunoglobulin G4(+) HT, which may occur as isolated thyroid limited disease or as part of a generalized Ig4-related sclerosing disease. The relationship between HT and Riedel thyroiditis remains unclear; however, recent evidence seems to suggest that it may also be part of the spectrum of Ig4-related sclerosing disease. HT is frequently associated with papillary thyroid carcinoma and may indeed be a risk factor for developing this type of cancer. The relationship between thyroid lymphoma and HT on the other hand appears well established.