Riedel's Thyroiditis: Report of Two Cases and Literature Review

IgG4-related sclerosing thyroiditis (Riedel-Struma): a review of clinicopathological features and management

We present a thorough review of the literature on Riedel thyroiditis (RT) with emphasis on aetiology, diagnosis and management, using the PubMed, Sinomed, and China National Knowledge Infrastructure databases. Although the exact aetiology of RT remains obscure, the histopathological features are consistent with a localized form of IgG4-related systemic disease (IgG4-RSD). Nevertheless, IgG4-RSD as a systemic fibroinflammatory disorder per se rarely affects the thyroid in the context of multiorgan manifestations. The initial diagnosis of RT is based on clinical history and imaging, but confirmation by histopathological examination is mandatory. In contrast to the historical surgical approach, glucocorticosteroid therapy is currently considered first line therapy, in line with the RT currently being viewed as a manifestation of, or analogous to, IgG4-RSD. For disease relapse, immunomodulatory agents (azathioprine, methotrexate, rituximab) can be used.

Riedel's Thyroiditis: Pitfalls in Diagnosis and Subsequent Complications

Riedel's thyroiditis is a rare disease of chronic inflammation with fibrotic infiltration of the thyroid gland and its surrounding vital structures. Due to its low incidence, there are often delays in diagnosis as it is commonly mistaken for other thyroid diseases. We report the case of a 34-year-old female patient who presented with a firm, enlarged mass in the neck, compression symptoms, and hypothyroidism. Lab tests showed elevated A-TG (thyroglobulin antibodies) and A-TPO (thyroid peroxidase antibodies) levels. Based on the disease presentation and supporting lab findings, the patient was misdiagnosed with Hashimoto's thyroiditis and treated accordingly. Yet the patient's symptoms grew progressively worse. She was discovered to have severe tracheal compression and bilateral RLN (recurrent laryngeal nerve) palsy. Tracheotomy became a necessary surgical intervention after the development of respiratory failure, but this procedure was complicated by the development of an intraoperative pneumothorax. After an open biopsy, histology revealed Riedel's thyroiditis. A new treatment was introduced, with which the patient's condition improved. However, she continued to suffer from the open tracheocutaneous fistula left by the tracheostomy, which adversely affected her everyday life. A follow-up operation was performed to close the fistula. In this case report, we discuss the consequences of misdiagnosing the patient and delaying the appropriate treatment for her disease.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Reidel's Thyroiditis, a Diagnostic and Management Challenge: A Case Report and Review of the Literature

Riedel's thyroiditis is a very rare inflammatory condition. It affects not only the thyroid gland but also the adjacent vital structures. It may also be associated with different forms of systemic fibrotic disorders. The exact etiology is unknown, but currently, the most favorable opinion is that it is a localized form of the systemic fibrotic process. We report the case of a 38-year-old woman, presented with a 10-month history of progressive hypothyroidism, dysphonia, and dysphagia. A Doppler ultrasound study revealed massive thyroid enlargement with multiple Eu TIRADS 3 and 4 nodules. Fine needle aspiration was noncontributive on two occasions. A hard subtotal thyroidectomy was performed. Pathological study confirmed Riedel's thyroiditis with the presence of IgG4 antibodies in immunohistochemistry. The patient was successfully treated with levothyroxine replacement and corticosteroid therapy with rapid resolution of obstructive symptoms. The case descriptions highlight the diagnostic challenge of this disease, describe the response to surgical management and corticosteroid therapy, and give a short review of the subject.

IgG4-Related Fibrous Thyroiditis (Riedel's Thyroiditis): A Case Report

BACKGROUND Riedel's thyroiditis is a rare form of immunoglobulin G (IgG) 4-related invasive fibrosis of the thyroid gland; given its scarce incidence, standardized therapeutic guidelines are unavailable. Although complications are unusual, obstructive symptoms produced by the stony-hard goiter may put patients' lives at risk. The diagnosis must be biopsy-proven, and treatment consists of thyroid hormone replacement and anti-inflammatory drugs, although sometimes thyroidectomy may be required. CASE REPORT A 69-year-old woman presented with a 7-month history of progressive hypothyroidism and obstructive dysphagia. On physical examination, she had a large, stony-hard goiter. A Doppler ultrasound study revealed a massive, avascular enlargement of the thyroid gland. A computed tomography scan failed to demonstrate any extrathyroidal extension of the abnormal tissue. A Tru-Cut biopsy of the thyroid was performed. Extensive replacement of thyroid follicles by prominent bands of fibrous tissue was observed, with follicular obliteration and mild focal occlusive phlebitis. A lymphoplasmacytic infiltrate was clearly identified; no oxyphilic nor giant cells were found. On immunohistochemistry, the immunoglobulin G (IgG) 4/IgG ratio in the plasma cell infiltrate was 40%; increased serum IgG4 levels were also found, supporting the diagnosis of Riedel's thyroiditis. The patient was successfully treated with levothyroxine replacement and tamoxifen with prompt resolution of obstructive symptoms. CONCLUSIONS Fibrous thyroiditis should be considered in the differential diagnosis of primary hypothyroidism in a patient with a stony-hard goiter. Although steroids are often used as a therapeutic strategy for this disease, our patient had an excellent therapeutic response to tamoxifen, avoiding adverse effects associated with steroid therapy, the higher cost of monoclonal antibody therapy, and surgery-associated risks.