Riedel’s Thyroiditis: Pitfalls in Diagnosis and Subsequent Complications

Abstract

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.

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

“…Riedel’s thyroiditis results in a thyroid gland that is mostly firm (“woody”, “stony”, or “iron-hard”) and enlarged causing local pain, compressive symptoms (dyspnea, dysphagia, hoarse voice, respiratory insufficiency), and hypothyroidism (up to 80% of cases) in association with extra-thyroid fibrosis; unusual complications such as exophthalmos, Horner’s syndrome, or venous sinus thrombosis have been found as well [ 2 , 4 , 6 ].…”

“…A high amount of IgG4-carrying plasma cells represents the novel clue of RT. Of course, in order to provide the histological and immunohistochemistry features, an open/core needle biopsy is necessary (unless a thyroidectomy was already performed); thus, an index of suspicion should be kept in mind even in the early stages of the disease when classical clinical signs are not yet very suggestive [ 2 , 6 , 10 ].…”

“…Misdiagnosis as Hashimoto’s thyroiditis (mostly due to positive serum antibodies against the thyroid) or as a thyroid malignancy, particularly of anaplastic carcinoma, sarcoma, or primary thyroid lymphoma, is often described considering the anatomical aspects and progressive (severe) clinical evolution [ 2 , 11 ]. Delay of the diagnosis underlines a time window from presentation to histological confirmation varying between a few months and 2 years (a median of 4 months) [ 2 , 6 ].…”

“…This selective estrogen receptor modulator is beneficial not through its anti-estrogen capacity but via anti-fibrotic effects by stimulating transforming growth factor (TGF- β ), a cytokine released by fibroblasts and epithelial cells acting as a growth inhibitor of various cells (including fibroblasts) [ 12 , 13 ]. The need for anti-fibrotic effects also indicates mycophenolate mofetil (1 g twice per day) which is approved for systemic fibrosis, but it has limited applications due to severe side effects (pancytopenia or renal function damage) [ 2 , 6 , 14 ].…”

“…Low-dose radiation therapy at the thyroid level represents a rarely applied alternative [ 15 ]. Surgery, despite not being a first choice of therapy, is useful for surgical biopsy (since fine needle aspiration is not helpful in more than 75% of cases), for refractory cases to medical therapy, or for emergency tracheostomy [ 2 , 4 , 6 ]. Generally, the presence of fibrosis and invasion of surrounding areas increases the rate of post-thyroidectomy complications or failure to completely remove the thyroid gland [ 16 , 17 , 18 ].…”