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

Abstract

Patient: Female, 69-year-old Final Diagnosis: Riedel thyroiditis Symptoms: Dysphagia • goiter Medication: — Clinical Procedure: — Specialty: Endocrinology and Metabolic Objective: Rare disease 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.

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

“…Since 2019, nine case reports of a single patient per paper have been published according to our methods [ 6 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 ] ( Table 2 ).…”

“…Serum IgG4 might not be increased in local (thyroid) forms of RT (with no other spreading of IgG4-RD) while immunohistochemistry provides a meticulous insight into IgG4-positive staining, which provides a clue regarding the specific case (regardless of the concentration of the serum IgG4 profile) [ 45 ]. Five out of the nine single case reports had a serum IgG4 assay available (only 2/5 had higher than normal values), while all subjects had a histological confirmation of the condition [ 6 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 ].…”

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

“…e incidence is now estimated to be 1 in 100,000, with higher incidence in women. It is most frequent in middle age adults (30-50 years) [2,3]. ere are multiple hypotheses regarding its pathogenesis, but its exact etiology remains uncertain.…”

“…It is a rare condition, with a prevalence of 1 per 100,000 inhabitants, which affects more frequently women between 30 and 50 years of age. RT accounts for less than 0.06% of patients undergoing thyroidectomies [3]. e precise etiology of this disorder is still unclear.…”

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

“…Currently, no acute overdose of tamoxifen has been observed [ 10 , 11 , 15 , 18 , 19 , 24 , 31 , 43 , 45 , 47 , 78 , 97 , 107 – 110 ]. It is noted that tamoxifen is used in other inflammatory conditions related to multifocal fibrosis [ 108 ].…”