A rare fibrotic condition that results in the destruction of the thyroid and overgrowth of progressively fibrosing connective tissue that may invade surrounding structures.There is no robust epidemiologic data; incidence is 0.06% to 0.98%; it is more common in women between 30 and 50 years of age.
It can be associated with other fibrosing processes such as sclerosing cholangitis, pancreatitis,mediastinitis, lacrimal fibrosis, orbital fibrosis, and fibroinflammatory lesions of the head and neck region.
A simple memory aid or mnemonic for Riedel Thyroiditis
Riedel thyroiditis – The thyroid is as “hard as Rye Bread”
Summary of clinical features
Etiology: No known cause
Clinical symptoms• Dysphagia• Dyspnea• Hoarseness• Aphonia
Physical ExaminationThe thyroid appears as a firm anterior neck mass with a “rock-hard” consistency. This firm mass may sometimes be interpreted as being a malignant lesion by the uninitiated.
Diagnosis and prognosis.Primary hypothyroidism and anti-thyroid peroxidase antibodies are present in most patients.Patients can also develop hypoparathyroidism due to infiltration of the parathyroid glands. High proportions of IgG4-plasma cells have been observed histologically but not always. Serum IgG4 is elevated.
Riedel thyroiditis is a progressive fibroinflammatory condition of the thyroid which may on rare occasion either stabilize spontaneously or sometimes regress.
TreatmentHigh-dose steroids: improvement in the size of the thyroidTamoxifen: proposed mechanism of action: induction of autocrine secretion TGF-beta 1 and the potential inhibition of fibroblastic functionSurgery: It includes debulking limited to isthmusectomy to relieve constrictive pressure to total thyroidectomy if compression symptoms are severe.
