Riedel's thyroiditis treated with tamoxifen

A 46-year-old woman with clinical diagnosis of Riedel's thyroiditis was admitted to our Department, presenting with dyspnea, dysphagia, fatigue, and hoarseness. Previously, she had been diagnosed with Hashimoto's thyroiditis and hypothyroidism. The disease had a progressive course and had lasted for a year before the definitive diagnosis of Riedel's thyroiditis was confirmed and treated with methylprednisolone, 12 mg daily, without success. We started therapy with tamoxifen, 10 mg twice a day, together with methylprednisolone, 16 mg daily, and L-thyroxin substitution therapy. The follow-up lasted for one year. Treatment with tamoxifen led to a significant subjective improvement and objective changes, confirmed by regular clinical examinations, ultrasonography, and computed tomography of the neck. After 8 months of therapy, the patient had no compression symptoms and goiter decreased in estimated weight from 105 g to 63 g according to ultrasound measurements. The patient underwent partial thyroidectomy at 10 months after diagnosis of Riedel's thyroiditis. Histopathology confirmed the diagnosis of Riedel's thyroiditis. Our report indicates that tamoxifen can be a valuable drug therapy in the treatment of Riedel's thyroiditis.