Riedel Thyroiditis

Excerpt

Riedel fibrosing thyroiditis is a rare disease characterized by chronic inflammation and fibrosis of the thyroid gland. It is also known as Riedel struma, ligneous struma, or chronic invasive fibrous thyroiditis. Classically, it presents as hypothyroidism with a "stone-like, hard-as-wood" non-tender thyroid gland.

Over time, the thyroid parenchyma and surrounding structures are replaced with dense fibrous tissue, leading to the destruction of the follicular cells of the thyroid gland. The fibrosis then extends to involve local structures, such as the airways. This causes obstructive symptoms such as dyspnea, dysphagia, and hoarseness due to airway compression. It can also present with hypothyroidism, hypoparathyroidism, or Horner syndrome.

Diagnosis can be made clinically with a physical exam; however, a biopsy showing dense fibrous tissue with a characteristic eosinophilic infiltrate is needed for confirmation. Management includes both medical therapy and surgery for symptomatic relief. The mainstay of treatment is glucocorticoids which can cause a dramatic improvement in the symptoms. Alternatives include tamoxifen, mycophenolate, and radiation in situations where the patient is non-responsive to steroids. Surgery is indicated when all other alternatives have failed or when the patient has symptoms of airway compression.