Riedel's Thyroiditis Research Articles

Utility of Sonoelastography and Magnetic Resonance Imaging in Characterization of Thyroid Nodules.

To evaluate thyroid nodules with sonoelastography and magnetic resonance imaging (MRI). The study included 28 patients with 40 thyroid nodules. Clearance was obtained from the institute's ethical clearance committee. Patients with pure cystic nodules or nodules with eggshell calcification, diffuse thyroid pathology (such as Graves' disease, Hashimoto's thyroiditis, De Quervain thyroiditis, and Riedel's thyroiditis), inaccessible nodules via fine needle aspiration cytology (FNAC), or patients with a history of thyroid gland surgery were excluded from the study. Strain elastography was performed on a Phillips iU22 machine, producing qualitative color-coded strain maps (graded using the Rago 5-point system) and semiquantitative strain ratios. MRI was performed on a Phillips ACHIEVA 1.5T magnet with a head and neck coil. Rago scores statistically correlated (χ2 = 18.052, p < 0.001) with malignant nodules, and using the receiver operating characteristic (ROC) curve, the area under the ROC curve (AUROC) for the mean strain ratio predicting malignant outcomes was 0.88 [95% confidence interval (CI): 0.767-0.992], which was also statistically significant (p < 0.001). A cutoff of mean strain ratio ≥2.48 predicted malignant outcomes with 100% specificity. T2 signal intensity ratio (SIR) and apparent diffusion coefficient (ADC) values were not statistically significant in predicting malignant outcomes. Kinetic curves were statistically significant for Rago scores (χ2 = 11.356, p = 0.045); however, no significant difference was found in predicting malignant outcomes. We concluded that sonoelastography, along with grayscale ultrasound, is a useful noninvasive technique for predicting histological outcomes. However, MRI should largely be reserved as a problem-solving tool rather than a standalone imaging modality. The kinetic curves show some degree of overlap between histologically distinct diseases, and thus large-scale multicenter trials are needed for further standardization.

Life-threatening airway obstruction by Riedel's thyroiditis: a rare presentation and diagnostic dilemma.

Riedel's thyroiditis is the rarest form of thyroiditis, occasionally resulting in rapid thyroid enlargement and potential tracheal obstruction. Here, we detail the case of an 81-year-old woman with a medical history including Hodgkin lymphoma, Hashimoto's thyroiditis, and multinodular goiter. She presented to the emergency room with stridor, cervical swelling, and breathing difficulties for over 2 days. CT scans revealed substantial thyroid enlargement causing significant glottal and tracheal compression, to a minimum tracheal diameter of 7 mm. Due to the severity of the compressive symptoms, orotracheal intubation and mechanical ventilation were deemed necessary. Surprisingly, despite the initial suspicion of malignancy given the rapid growth in the elderly, subsequent cytological and histological evaluations indicated a benign form of invasive fibrous thyroiditis - Riedel's thyroiditis. Although surgical intervention was advised, the patient declined and opted for endobronchial treatment with a prosthetic stent and subsequent treatment with systemic glucocorticoids. Following successful treatment, she was discharged within a week and resumed normal activities without respiratory distress. This case is noteworthy for its rapid benign mass growth, rare emergent presentation, and the patient's advanced age. The rapid enlargement of the thyroid gland in elderly patients poses a diagnostic challenge, stemming from the higher occurrence of aggressive thyroid carcinomas. Despite the clinical presentation, a comprehensive diagnostic workup, including fine-needle aspiration and core-needle biopsy, is crucial for accurately distinguishing between benign and malignant causes of thyroid nodule enlargement. This case report illustrates diverse treatment options for Riedel's thyroiditis, and the importance of individualized treatment plans based on the degree of airway obstruction, patient preferences, and response to initial interventions. Clinicians should contemplate the inclusion of glucocorticoids in the therapeutic regimen for Riedel's thyroiditis, particularly in cases where surgical intervention is not feasible or declined by the patient.

Riedel's thyroiditis: report of 7 patients and review of literature.

Riedel's thyroiditis is a rare inflammatory-sclerosing thyroid disease, and its aetiology remains unknown. After a surgical biopsy to establish the diagnosis, the treatment of Riedel's thyroiditis is still challenging in most patients. The aim of this article is to report seven patients with Riedel's thyroiditis seen in a department of Endocrinology and Metabolic diseases over a period of 24 years, and based on the patient's data and the review of the literature to discuss the indications of surgery, glucocorticoids, tamoxifen and immunosuppressive drugs in the personalized treatment of patients with Riedel's thyroiditis.

IgG4-related disease: an update on pathology and diagnostic criteria with a focus on salivary gland manifestations.

Immunoglobulin G4-related disease (IgG4-RD) is a multi-organ disorder characterized by a highly variable clinical presentation depending on the affected organ/s, extent of tumefactive fibroinflammatory lesions, and associated functional impairment. The disease pursues a chronic, relapsing, often asymptomatic course and hence may pose a significant diagnostic challenge. Diagnostic delay can lead to progressive fibrosis and irreversible organ damage resulting into significant morbidity and even mortality. Given its broad clinical spectrum, physicians of all specialties may be the first clinicians facing this diagnostic challenge. Outside the pancreatobiliary system, the head and neck represents the major site of IgG4-RD with variable organ-specific diffuse or mass-forming lesions. In up to 75% of cases, elevated serum IgG4 levels are observed, but this figure possibly underestimates the fraction of seronegative cases, as the disease manifestations may present metachronously with significant intervals. Together with negative serology, this can lead to misdiagnosis of seronegative cases. A standardized nomenclature and diagnostic criteria for IgG4-RD were established in 2012 and revised in 2020 facilitating scientific research and expanding the range of diseases associated with IgG4 abnormalities. In addition to orbital pseudotumor, dacryoadenitis, Riedel thyroiditis, sinonasal manifestations, and rare miscellaneous conditions, IgG4-related sialadenitis is one of the most frequent presentations in the head and neck region. However, controversy still exists regarding the relationship between sialadenitis and IgG4-RD. This review focuses on the clinicopathological features of IgG4-related sialadenitis and its contemporary diagnostic criteria.

P-66 Primary Thyroid Lymphoma mimicking Riedel Thyroiditis

Abstract Introduction Although Riedel's thyroiditis and primary thyroid lymphoma are rare diseases of the thyroid, they should be considered in the differential diagnosis of patients presenting with a neck mass. We report here the case who was followed up with the diagnosis of Riedel's thyroiditis and later diagnosed with lymphoma. Clinical Case A 67-year-old female presented with swelling in the neck, pain and shortness of breath. Thyroid ultrasound demonstrated enlarged thyroid gland, heterogeneous parenchyma, irregular contours, thin septations and pseudonodule formations. Laboratory tests revealed, TSH 4.17 mIU/L, fT4 1.37 ng/dl, anti TPO 147 IU/mL, sedimentation 13mm/h, and CRP of 5.5 mg/dl. In neck CT, an 8*4 cm hypodense mass infiltrating both thyroid lobes, extending anteriorly and superiorly, surrounding the trachea by 270 degrees, was detected. Follicle cells were seen in the fine needle aspiration biopsy, but no neoplasm was found. In PET-CT, increased FDG uptake was detected in the thyroid parenchyma (SUVmax: 22.89) and in one subcentimetric lymph node (SUVmax: 3.5) in the right cervical region. No neoplasm was found in the tru-cut biopsy and the biopsy was reported as granulomatous thyroiditis. When her current complaints and physical examination findings were evaluated together, methylprednisolone was started, considering Riedel's thyroiditis. In the follow-up examination, the thyroid size of the patient decreased significantly and the steroid dose was reduced. The patient, who could not be followed up for a while, developed swelling and pain in the neck again, and was followed up in the ICU with acute respiratory failure, a tracheal stent was applied to the patient. The patient was then followed in the ward, with dyspnea, dysphagia and hoarseness continued, was admitted to our polyclinic again and was hospitalized. The patient stated that her oral intake decreased due to dysphagia and there was a loss of 40 kg. She had no fever or night sweats. She was not smoking. Physical examination revealed a hard, fixed mass that completely filled the right neck and reached the midline. In the endoscopic examination, the vocal cords were paralytic, the air passage was inadequate, and the mass was invading the trachea. Tracheostomy was applied to the patient. Trucut biopsy was taken from the thyroid tissue. In addition, PET-CT was taken. On PET-CT, right thyroid dimensions showed significant morphological progression compared to the previous study, very dense at similar levels (previous SUVmax: 22.89,current SUVmax: 22.76);intense FDG uptake was detected in 8 mm lymph nodes in the left cervical and 19×20 mm lymph nodes in the right supraclavicular (SUVmax 22.17) region.Diffuse Large B-Cell Lymphoma was detected as a result of thyroid biopsy and R-CHOP treatment was started on the patient. She was discharged after 2 cycles of chemotherapy (Figure). The diagnosis of both Riedel's thyroiditis and primary thyroid lymphoma are histopathological. The importance of open surgical biopsy and cooperation with an endocrine-specific pathologist was emphasized through our case.Figure.Photos of the patient at her initial and last state

P-82 Riedel's thyroiditis: three-year follow-up under steroid, rituximab and mycophenolate mofetil treatment

Abstract Introduction Riedel's thyroiditis (RT) is an uncommon thyroiditis characterized by fibrosis, macrophage, and eosinophil infiltration and is assumed to be the primary cause of autoimmunity in the pathogenesis. Invasion of the surrounding tissues, particularly the trachea, occurs. RT is also regarded as thyroid involvement in IgG4-related systemic illness. Because there is no conventional medical treatment protocol for RT, this paper aims to highlight the problems we had in diagnosing and our approach throughout therapy. Clinical Case In the last 1.5 years, a 44-year-old female patient on levothyroxine replacement diagnosed with hypothyroidism developed bilateral swelling in the eyes, double vision, drooping eyelids, shortness of breath, and feeling something lodged in the throat. A diffusely enlarged and stiff thyroid gland was palpated in her physical examination. Neck CT revealed a diffusely enlarged thyroid gland 7cm in diameter and constricted trachea. She did not have any constitutional symptoms. According to physical and radiologic exams, preliminary differential diagnoses were anaplastic thyroid carcinoma and IgG4-related thyroiditis. In laboratory tests, TSH: 4.5 mIU/L, st3-4: normal, Anti TPO: +++ TRAB: 0.15 U/L, ANA: Negative, IgG4: 0.52 g/L (0.03-2.01), ACE:21.39. Since the thyroid fine needle aspiration biopsy reported a hypocellular smear, a lacrimal gland biopsy was performed for systemic involvement of IgG4 related disorder's. Her dyspnea was becoming critical; therefore, she was administered 0.5 mg/kg steroid for two weeks before the scheduled bilateral total thyroidectomy, and a considerable decrease in dyspnea, swallowing sensations, and regression in compression findings were seen. Lacrimal biopsies demonstrated persistent inflammation with plasma cells and severe fibrosis, consistent with late-stage IgG4-related illness. Both thyroid lobes were enlarged in neck T1 and T2-weighted MRI images (right lobe was 34×25×68 mm, the left lobe was 35×26×69 mm), diffuse hypointensity was noted, contrast uptake decreased in the thyroid parenchyma following IVCM, and the data was determined to be compatible with RT. The thyroid gland grew markedly on PET-CT, narrowing the air column, with increased FDG absorption in a heterogeneous character (SUVmax: 4.9), and mild-moderate involvement in bilateral lacrimal and parotid glands.The decision was made to continue steroid treatment at 1 mg/kg for one month. Rituximab was given twice every six months while the steroid was lowered. Mycophenolate mofetil (MMF) (2×500 mg) was introduced as a maintenance immunosuppressive medication. The initial radiologic findings regressed in the control neck MRI and PET-CT in the first year. The MRI findings were also steady in the second and third years of MMF. Conclusion Immunosupression therapy with steroid, rituximab and MMF was effective in our RT patient for the long term without significant complications. Clinical and radiological responses similar to surgery can be obtained with immunosuppressive agents.Figure 1.PET-CT and MRI images at diagnosis and third year

The clinical case of IgG4-related thyroid disease in a 6-year-old child

IgG4-related disease is a rare chronic pathology manifested by lymphoplasmacytic infiltration of one or more organs, the formation of storiform fibrosis, tissue edema, and an increase of IgG4 in the blood. This disease was singled out as an independent nosological unit only in 2001. The incidence is less than 1 in 100,000 people per year. Almost any organ can be affected in IgG4-related disease. The association of Riedel's thyroiditis with IgG4 was established in 2010.Riedel's thyroiditis is an extremely rare inflammatory disease of the thyroid gland, which diagnosis is complicated by an atypical course and the absence of characteristic symptoms. Less than 300 clinical cases of the disease have been described in the world, only two from them were in children. This article presents a clinical case of a 6-year-old boy with Riedel's thyroiditis.

Ultrasonic follow‐up of a methotrexate‐treated patient with Riedel's thyroiditis

Ultrasonic follow‐up of a methotrexate‐treated patient with Riedel's thyroiditis

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

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

VASCULAR COMPLICATIONS IN LYMPHOCYTIC THYROIDITIS – SONOGRAPHIC FINDINGS

Objective: Alert to the ultrasonographic findings of cervical vascular involvement in the context of lymphocytic thyroiditis, since it is a rare situation. Design and method: CASE DESCRIPTION: Male patient, 87 years old, caucasian, diagnosed with lymphocytic thyroiditis since 2004, euthyroid, stable until 2019, presenting an enlarged thyroid volume on that date. He has a history of ischemic stroke in 2003. In 2019, he underwent a thyroid ultrasound where the hypothesis of intraluminal thrombus of the right internal carotid artery was raised. The evaluation with cervical vascular ultrasonography revealed an iso-hypoechogenic, heterogeneous image, lining the arterial wall, in the proximal segment of the internal carotid arteries, without hemodynamic repercussions, compatible with a probable inflammatory/fibrous infiltrate, in the context of lymphocytic thyroiditis. Computed Tomography scan of the thyroid and soft tissue confirmed the progression of the adjacent soft tissue infiltrate. Results: DISCUSSION: Taking into account the size of the inflammatory changes and the fact that the patient remains euthyroid, it is important to question about a the possibility of an evolution/adjustment of the disease previously diagnosed in 2004 to a new one: Riedel's thyroiditis, also known as an invasive fibrous or sclerosing thyroiditis. Riedel's thyroiditis is a pathological condition with an unknown etiology that causes a fibro-inflammatory infiltrative stated in the 2019 examination. Considering the low prevalence of the pathology, it is important to alert sonographers to the possible vascular complications observed in a supposed Riedel's thyroiditis, in order to make a reliable evaluation and diagnosis of the cervical vascular ultrasonographic findings. Conclusions: Regarding the monitoring of lymphocytic thyroiditis, it is just as important to do a periodic evaluation of the dimensions, characteristics of the gland and analytical evaluation of the thyroid function, as it is to monitor the infiltrate of adjacent tissues, namely vascular, to prevent possible serious complications.

Two rare cases of Riedel's thyroiditis

Searchable abstracts of presentations at key conferences in endocrinology ISSN 1470-3947 (print) | ISSN 1479-6848 (online)

Abstract #1385480: Goiter and Abdominal Mass: A Rare Presentation of Riedel’s Thyroiditis

Riedel’s thyroiditis (RT), also known as fibrous thyroiditis, is a rare inflammatory autoimmune disease that is often associated with various forms of systemic fibrosis such as sclerosing mesenteritis (SM). A 38-year-old female with a past medical history of hypertension presented with a painful growing goiter and a mesenteric mass, which was complicated by biliary obstruction and hydronephrosis. Physical exam showed tenderness on the abdomen and a diffusely enlarged firm thyroid gland, with no palpable nodules. Initial labs revealed C-reactive protein of 115 mg/L, TSH 180 mIU/L; Free T4: 0.79 ng/dL, positive Thyroid Peroxidase (>1051 IU/mL); normal IgG1 and IgG4. CT abdomen/pelvis demonstrated a mesenteric mass that encased multiple mesenteric vessels and the right ureter without bowel obstruction. Thyroid ultrasound showed an enlarged heterogeneous thyroid without a discrete nodule consistent with autoimmune thyroiditis. Thyroid fine needle aspiration (FNA) was non-diagnostic. Thyroid biopsy showed mostly fibrosis with scattered lymphoplasmacytic aggregates, with no evidence of carcinoma, lymphoma, IgG4-related disease, and no Hürthle cell presence. Interestingly, the mesenteric mass biopsy revealed the same pattern. Peripheral flow cytometry and infectious workup were negative. Diagnosis of RT and SM were made. The patient was treated with steroids and improved clinically. The hallmark of RT is the extension of fibrosis beyond the thyroid. This patient exhibited common features of RT such as neck pressure, and pain; female gender, elevated inflammatory markers, nondiagnostic FNA (scant cellularity due to fibrosis), and a positive steroid response. Moreover, intense infiltrative fibrosis mixed with lymphocytes and plasma cells instead of an extensive lymphocytic infiltrate with the germinal center formation on histology supports Riedel’s thyroiditis rather than Hashimoto's. Similarly, SM is a rare, non-neoplastic inflammatory and fibrotic disease that affects the integrity of mesenteric vessels causing common bile duct and ureter obstruction. Negative flow cytometry, the presence of sclerosis, and the absence of bowel/liver lesions involvement make other common causes of a mesenteric mass (lymphoma, desmoid tumor, carcinoid) less likely, supporting the diagnosis of SM. The concurrent timing of her thyroid enlargement and the mesenteric mass as well as the similarity in histology (dense fibrosis with patchy lymphoplasmacytic aggregates) suggests an association between RT and SM. Overall, the case highlights the challenges in diagnosing RT given its extreme rarity and emphasizes the importance of early treatment to prevent systemic involvement.

Potential impact of autoimmune diseases family history in IgG4-related disease: a retrospective cohort study

ObjectiveAutoimmune comorbidities may be associated with IgG4-related disease (IgG4-RD), here we aimed to determine the correlation of autoimmune diseases (AID) family history and IgG4-RD in a Chinese cohort.MethodsThis retrospective cohort...

A rare case of Riedel's thyroiditis: Immunoglobulin G4-related thyroid disease

Abstract Introduction Riedel's thyroiditis is a rare thyroiditis in which normal thyroid tissue is replaced by dense fibrous connective tissue. Its etiology is not fully known. An autoimmune process is thought to exist. In this disease group, lymphoplasmocytic tissue infiltration, mostly consisting of IgG4 (+) plasma cells and small lymphocytes, is seen accompanying fibrosis. In our case, we presented a very rare case of Reidel's thyroiditis. Clinical Case We report the case of a 46-year-old woman who came to the general surgery department with an enlargement at the base of her neck. Among the patient's complaints were dysphonia, a feeling of pressure and pain in the neck. She had no history of thyroid disease. Laboratory findings; TSH 0.06 uIU/ml (0.27–4.2), fT3 2.69 pg/mL (2.3–4.5), fT4 1.81 ng/dl (0.93–1.70), crp 73.6 mg/l (0.0–5.0), sedimentation 90 mm/h (0–20), leukocytes 11.74 10^3/ul (4.49–12.68), absolute neutrophil count 9.22 10 ^3/ul (1.9–7.9). Trucut biopsy was performed with the preliminary diagnosis of malignancy due to the history of a mass growing in a short time on the neck of the patient. Pathology result; “Intense fibrosis increase, severe lymphoplasmacytic cell infiltration rich in IgG4 positive cells. Thyroid follicle epithelial cells with ck7, panck, pax8, thyroglobulin, ttf1 positive and cea, ck20, alk negative Intense plasma cells with CD38 have polyclonal staining with kappa and lambda, and IgG4/IgG ratio &amp;gt; 50%. In the background, cd3, pax5 and bcl2 and T cell-rich reactive inflammatory cells are accompanied. Obliterative vascular structures were noted in rust and elastic histochemical stains, and storiform fibrosis was observed in places on the ground. When histopathological and immunohistochemical findings are evaluated together, it is primarily compatible with IgG4-related disease/reidel thyroiditis.'' She was then referred to the endocrinology department. The serum IgG4 level was found to be above normal. She was started on steroid treatment with 64 mg daily methylprednisolone. A weekly control plan was made. In these controls, the steroid dose was gradually reduced. In the follow-up one week later, it was observed that the patient's CRP and sedimentation returned to normal values. There was also a decrease in enlargement in the neck area. In the third month of the treatment, the patient didn't want to continue the treatment. She did not visit our clinic for the next 3 months. Then, she came for the control after three months without treatment. Biochemistry and thyroid function tests were normal. The swelling in the neck area of the patient was completely gone. Conclusion Reidel's thyroiditis is a very rare disease with publications on the basis of case reports in the literature. Therefore, there are no broad-spectrum clinical studies. Clarity on treatment approaches was also not provided. We also benefited from case reports while managing our patient's treatment. We believe that our case will contribute to the literature for the same purpose.

IgG4-associated sclerosing thyroiditis: one case, two different clinical courses

Abstract IgG4 related Diseases (IgG4- RD) are characterized swelling of affected organs, elevated levels of serum IgG4, dense lymphocyte infiltration and IgG4- positive plasma cells in tissues pathologically in the involved organs. 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. We present a case of changing between subtypes of IgG4-related thyroid disease—transition from GD to IgG4-related sclerosing thyroiditis for the first time in the literature. A 48-year-old female patient, who had a diagnosis of psoriasis, and asthma, was admitted to the hospital due to fatigue complaint in 9/2012. Her laboratory assessment was compatible with thyrotoxicosis. It was detected patchy hypoechoic areas within the gland and Vitti 3 blood in the parenchyma in the thyroid doppler ultrasonography (USG). The results were compatible with Graves disease (GD) and methimazole (MMI) and beta blocker treatment were started at diagnosis. Rapid changes in serum thyroid function tests (TFT) in 1–3 months of follow-up were observed under MMI treatment. The patient first described a pressure during swelling in her throat in 8/2016. Grade 3 goiter was detected in her physical examination (PE). The patient had unstable TFT and received short term-intermittent MMI treatment according to TFT results until 9/19. MMI was discontinued upon detection of TSH 29.18(0.38–5.33) µIU/mL. After approximately six months of euthyroid follow-up, she was admitted to the outpatient clinic with complaints of hypothyroidism and compression due to grade 2 goiter. The thyroid is hard on PE. Her laboratory assessments were compatible with hypothyroidism and levothyroxine (LT4) treatment was started. The thyroid volume was 38 ml, the parenchyma was markedly echogenic, no compression sign in adjacent structures on USG. Thyroid tru-cut biopsy was planned with the preliminary diagnosis of Riedel/ IgG4 related disease. Histopathological diagnosis on tru-cut biopsy of thyroid was fibrosclerosing chronic thyroiditis with severe collagen fibrosis and interstitial lymphocyte infiltration. The presence of IgG4 positive plasma cells in the fibrotic stroma was remarkable and compatible with IgG4-associated sclerosing thyroiditis (Figure 1). The serum Ig G4 level was detected as 1.27 g/L(0.04–0.86). No sign of fibrosing disease was detected in neck, thorax and abdomen imaging. The results of laboratory and autoantibody levels are summarized in Table 1 and the Figure 2 and 3. Figure 1. Cytopathological evaluation A. Thyroiditis with diffuse collagen fibrosis and interstitial lymphoplasmacytic cell infiltration (chronic thyroiditis in the sclerosing/fibrotic stage). B. Fibroinflammatory reaction/chronic thyroiditis in core needle biopsy C. Immunohistochemistry: Intense IgG staining in interstitial lymphoplasmacytic cells, D. IgG4 positivity around 30% of IgG positive cells. We present a patient who initially presented with thyrotoxicosis, which was controlled with short-term MMI therapy, then transitioned to hypothyroidism, and the final diagnosis was IgG4-induced thyroiditis. IgG4-related thyroiditis includes IgG4-related Hashimoto's thyroiditis (HT), Riedel's thyroiditis, fibrosing variant of HT, and GD with elevated IgG4 levels. The clinical course of these subtypes is not exactly known due to their rarity.

Pictorial review of computed tomography and magnetic resonance imaging findings of cardiovascular manifestations of IgG4-related disease.

This study includes a series of 5 cases demonstrating cardiovascular manifestations of findings of IgG4-related disease. Two cases demonstrate peri-aortic soft tissue thickening in the infrarenal abdominal aorta and bilateral ostio--proximal common iliac artery. In 2 cases there were circumferential soft tissue lesions around the arch of the aorta. One of the cases showed coexistent, biopsy-proven Riedel's thyroiditis and infiltrative soft tissue along the right atrial wall and interatrial septum. In one case there was a partly calcified mass in the left hemi-thorax consistent with a diagnosis of IgG4-related fibrosing mediastinitis.

Abstract #1305018: Riedel’s Thyroiditis and Systemic IgG4 Disease: The Missing Link

Riedel’s thyroiditis (RT), is a rare form of multifocal fibrosis of the thyroid gland. Typical histopathology of Riedel’s thyroiditis has been described to show atrophy and inflammation of the thyroid parenchyma with dense fibrosis extending in the adjacent tissue. IgG4-related disease is a newly recognized fibroinflammatory condition characterized by fibrotic lesions at multiple sites, a dense lymphoplasmacytic infiltrate rich in IgG4-positive plasma cells, storiform fibrosis, and often but not necessarily, elevated serum IgG4 concentrations.

LBSAT310 A Rare Disease Engulfing Thyroid And Masquerading As Common Thyroid Disorders

Abstract Introduction – Langerhans cell histiocytosis (LCH) is a rare clonal disorder caused by the CD207+ Langerhans cells derived from the myeloid origin. We present a case of LCH where it mimicked Hashimoto's and Riedel's thyroiditis and completely infiltrated the thyroid gland. Case description – A 54-year-old female was initially diagnosed with hypothyroidism, goiter, and bilateral parotid and submandibular glands enlargement. CT imaging revealed a diffuse goiter which imposed infraglottic airway narrowing and a suspicious left inferior thyroid nodule. Biopsy revealed atypia of undetermined significance. GSC showed a 50% suspicion of malignancy with a negative BRAF. Follow up imaging revealed increased infiltrative masses within the salivary glands, enlarging thyroid gland, and increased infiltration of the superior component of the right thyroid lobe into the submandibular space. A core needle biopsy revealed a background of acute and chronic inflammation without evidence of malignancy. Sjogren's, sarcoidosis and IgG4 diseases were ruled out. She was then referred to us after a myriad of work up. She had a diffusely enlarged goiter with a crusted area of skin over the thyroid gland and significant bilateral parotid swelling. We repeated a thyroid ultrasound which revealed diffusely enlarged and heterogeneous thyroid glands with pseudo-nodules and 3 suspicious nodules greater than 1cm on right and left lobes. She also had prominent reactive lymphadenopathy. Her submandibular glands were hypoechoic, avascular, markedly enlarged and abnormal appearing. She underwent total thyroidectomy. Pathology revealed proliferation of histiocytes, few islands of lymphoid tissue, and eosinophilic micro abscesses without any identifiable thyroid parenchyma in the entire resected specimens. Immunohistochemistry confirmed the diagnosis of Langerhans Cell Histiocytosis with atypical features. BRAF (V600E/V600K) mutation was again not detected. Flow cytometry showed no evidence of neoplastic myeloid blast population. She was referred to an oncologist for further management of LCH. Discussion – Our patient had a remarkably diffuse goiter with a sonographic appearance mimicking Hashimoto's thyroiditis or Riedel's thyroiditis. Initial thyroid FNA failed to reveal LCH. The diagnosis was reached only after total thyroidectomy. Treatment depends on single or multi-system involvement, presence or absence of risk organ involvement, and presence or absence of BRAF mutation. Conclusion In the cases of infiltrated thyroid diseases, Langerhans cell histiocytosis should be on the differential diagnosis, especially if there is concomitant infiltrative process in other organs. The sonographic finding can mimic Hashimoto's or Riedel's thyroiditis which may lead to misdiagnosis and treatment delay. Presentation: Saturday, June 11, 2022 1:00 p.m. - 3:00 p.m.

ODP456 A rare case of massive goiter with overlapping features of Riedel's thyroiditis and Fibrous Variant of Hashimoto's thyroiditis

Abstract Background Hashimoto's thyroiditis is the most common autoimmune disorder of the thyroid gland associated with hypothyroidism. It is distinguished by painless inflammation and elevated titers of TPO antibodies. Fibrous Variant of Hashimoto's Thyroiditis is a rare condition occurring in about 10% of cases, mainly middle-aged individuals, and characterized by an extensive fibrous proliferation without extension into the surrounding structures. Riedel's thyroiditis is a rare generalized autoimmune disorder involving B lymphocytes and IgG4-secreting plasma cells, clinically characterized by extension of the fibrous process to surrounding tissues in the neck, as well as compression symptoms like dysphagia and dyspnea. It is usually associated with mediastinal and retroperitoneal fibrosis. There is significant clinical, pathological, and laboratory test overlap between these two entities that makes the differential diagnosis difficult. Case report A 54-year-old male diagnosed with hypothyroidism on Levothyroxine, and a large goiter seen with new onset of compressive symptoms including dyspnea and dysphagia since March/April 2021. He complains of having pressure on his neck, difficulty swallowing, and worse symptoms when lying flat on a bed. His thyroid is noted to be extremely large and firm, without evident nodularity on examination. Laboratory exams were significant for TSH 3.21 (0.36-3.74), T4 0.94 (0.76-1.46), vitamin D level 13 (30-100), TPO &amp;gt; 9000 (0-9), IgG4 81.9 (4. 0-86. 0), and a negative ANA screen. Thyroid ultrasound showed an enlarged heterogeneous thyroid gland with no discrete nodules. Given the compressing symptoms the patient presented, he was referred to surgery for total thyroidectomy. Surgery could not be completed due to the inability to safely mobilize the gland and adherence to surrounding tissues. He then underwent a right thyroid lobule core biopsy, showing an inflammatory infiltrate composed primarily of lymphocytes and plasma cells. Atrophic thyroid follicles with prominent fibrosis were noted. IgG4 immunostaining highlights &amp;lt;5 positive plasma cells/HPF and IgG4/IgG &amp;lt;30%, excluding IgG4-related fibrosing disease in this core biopsy material. There was no evidence of malignancy. Considering the prominent fibrosis, very high TPO Ab titer, and a seeming lack of extrathyroidal involvement, Fibrous Variant of Hashimoto's Thyroiditis seems more likely, but Riedel Thyroiditis cannot be completely ruled out. He was placed on Prednisone 40 mg daily, with modest improvement of symptoms. Tamoxifen 20mg daily was later added given literature reports of additional improvement in symptoms associated with its use. Referral to a tertiary center for possible isthmusectomy may be considered if symptoms worsen. Presentation: No date and time listed

Immunoglobulin G4-related endocrine diseases

Immunoglobulin G4-related disease has become the focus of interest in recent years. The disease is characterized by inflammation of the organs involved, often with a macroscopic appearance suggestive of a tumor, elevated immuno-globulin G4 levels, immunoglobulin G4-positive plasma cell infiltration on histological examination, fibrosis, oblit-erative phlebitis, and typically a rapid therapeutic response to corticosteroids. The disease can show a variety of organ manifestations, with frequent involvement of exocrine glands. Among the endocrine organs, symptoms may appear in the thyroid gland and the pituitary gland. The criteria for immunoglobulin G4-related hypophysitis were formu-lated in 2011. Until a few years ago, a condition formerly known as Riedel's thyroiditis was identified as immuno-globulin G4-related thyroiditis. Based on the criteria system for immunoglobulin G4-related thyroid diseases pub-lished in 2021, some patients with Hashimoto's thyroiditis and Graves' disease can also be classified as immunoglobulin G4-related thyroid disease. The identification of immunoglobulin G4-related endocrine diseases and the establishment of an accurate diagnosis can modify the treatment of the patient and determine the course of the disease. Other organ manifestations should be sought in patients with immunoglobulin G4-related endocrine disease and lifelong immunological follow-up is warranted.