Endocrine Abstracts

Introduction: Riedel’s thyroiditis (RT) is a rare chronic inflammatory disease characterized by a dense fibrosis that replaces normal thyroid parenchyma. The most common manifestation is a stony hard thyroid mass, commonly associated with compressive symptoms. Histological confirmation is essential for diagnosis and the main differential diagnosis is the anaplastic thyroid cancer. The management is challenging and there is no agreed standard treatment, since only a few cases have been described.

Clinical Case: Case 1: A 46-year-old woman presented with a 2-month history of painless anterior neck mass and dysphonia. Neck examination revealed a hard and painful thyroid mass. Blood tests showed subclinical hyperthyroidism and positive thyroglobulin antibodies (TgAbs). Ultrasound showed a 39 mm solid, hypoechoic and heterogeneous nodule with poorly defined margins. There was no cervical lymphadenopathy. Tc99m scintigraphy revealed a cold nodule. Fine-needle aspiration biopsy (FNAB) was non-diagnostic. The patient underwent total thyroidectomy, requiring postoperative emergency tracheostomy. Laryngoscopy revealed bilateral vocal cord paralysis. The histological study was compatible with RT. The tracheostomy was closed 8 weeks after surgery. Prednisolone 40 mg and, posteriorly, tamoxifen 20 mg were started with symptomatic relief. Both medications were tapered off. Currently, 7 years after diagnosis, the patient is asymptomatic.

Case 2 A 67-year-old woman with thyroid nodular disease was proposed for right hemithyroidectomy. Intraoperatively, a hard mass adhering to the trachea and right carotid artery was found, making resection impossible. Therefore, a intraoperative biopsy was performed to establish histological diagnosis. Histopathology was consistent with RT and the patient was referred to Endocrinology consultation. She had no compressive symptoms and physical examination revealed a 5 cm stony hard thyroid mass. There was no cervical lymphadenopathy. Blood tests showed hypothyroidism and positive TgAbs. Ultrasound showed a 52 mm solid, hypoechogenic and heterogeneous mass in the right thyroid lobe. A FNAB was performed with a non-diagnostic result. A neck CT confirmed a voluminous solid mass in the right lobe without cleavage planes with cervical vessels and trachea. Given the clinical stability and absence of symptoms, it was decided to maintain active surveillance. After 5 years of follow-up, the patient remains asymptomatic and the thyroid mass is stable on ultrasound.

Conclusion: Although malignancy is more frequent, in patients presenting with a hard thyroid mass RT should be considered as differential diagnosis. Our cases highlight the challenges inthe diagnosis and management of this rare disease and the importance of taking an individualized approach.