Riedel's thyroiditis masquerading as anaplastic thyroid carcinoma: a case report

INTRODUCTION: Riedel's thyroiditis is a rare thyroid disease characterized by dense fibrous tissues that replace the thyroid gland and invade the adjacent structures that can mimic thyroid malignancy. We discuss the presentation, investigation and management of this very rare condition. CASE PRESENTATION: We present a case of a 59-year-old African-Caribbean man who presented with a rapidly growing hard neck mass, a hoarse voice, dysphagia and breathing difficulty that clinically suggested thyroid malignancy. Biopsy, however, revealed dense fibrous tissues suggestive of Riedel's thyroiditis. This was successfully treated with very high dose steroids, with no relapse in the symptoms. CONCLUSION: It is important for clinicians to be aware of this diagnosis when managing patients with thyroid disease, because Riedel's thyroiditis can mimic malignancy. In addition, our case demonstrates that this condition should be treated with very high dose steroids to prevent relapse.