Riedel Thyroiditis Differential Diagnoses

Updated: Jul 22, 2022
  • Author: Chris K Guerin, MD, FACE; Chief Editor: George T Griffing, MD  more...
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Diagnostic Considerations

Riedel thyroiditis (RT) is characterized by the replacement of normal thyroid parenchyma with dense fibrotic tissue and by the extension of this fibrosis to adjacent structures of the neck. Most patients are euthyroid, but hypothyroidism is noted in approximately 30% of cases. Rarely, hyperthyroidism can occur, but this is probably secondary to a coexisting condition.

Clinical features of RT closely resemble those of anaplastic carcinoma of the thyroid. Patients note a nonpainful, rapidly growing thyroid mass.

Patients typically present with a hard, fixed, painless goiter. The character of the thyroid gland is often described as stony or woody. The onset of the goiter may be sudden, but it is usually gradual.

Local compressive symptoms are frequent and can include the following:

  • Neck tightness or pressure

  • Dyspnea

  • Dysphagia

  • Hoarseness

  • Choking

  • Cough

Such symptoms are the result of the increasing thyroid mass or are due to the extension of the fibrotic process to adjacent neck structures (eg, strap muscles, trachea, esophagus, recurrent laryngeal nerve).

Hypoparathyroidism is rare and presumably reflects fibrotic involvement of the parathyroid glands. Recurrent laryngeal nerve paralysis is also uncommon, but it can be observed in extensive disease.

Approximately one third of patients with RT have an associated extracervical manifestation of multifocal fibrosclerosis. These manifestations can include the following [8] :

  • Retroperitoneal fibrosis

  • Mediastinal fibrosis

  • Orbital pseudotumor

  • Pulmonary fibrosis

  • Sclerosing cholangitis

  • Lacrimal gland fibrosis

  • Fibrosing parotitis

Differential Diagnoses