fibrous thyroiditis, a rare disorder characterized by slowly progressive fibrosis of an enlarged thyroid, with replacement of normal thyroid tissue by dense fibrous tissue. The gland eventually becomes fixed to the adjacent muscles, nerves, blood vessels, and trachea by means of this fibrous tissue. The disease occurs more frequently in women than in men and usually arises after 40 years of age. Obstructive symptoms are uncommon but can include a choking sensation, dyspnea, and dysphagia. Hypothyroidism may occur, but in most patients the gland functions normally. Treatment includes surgical excision and thyroid hormone administered postoperatively, as required. Also called ligneous thyroiditis, Riedel’s struma, Riedel’s thyroiditis.
