A case of a patient with Rai-refractory differentiated thyroid cancer with progressive neck disease and stable lung metastases

Differentiated thyroid carcinoma is generally considered to have an excellent prognosis. However, a minority of patients initially present with risk factors for disease recurrence and progression, refractory to treatment with radioactive iodine (RAI). We herein report one such case, with recurrent RAI-refractory disease treated with neck surgery with the aim of decreasing tumor burden and limiting loco-regional tumor invasion. Case report: A 69-year-old male patient was referred to our institution after a 10-year history of treatment with surgery and radioactive iodine for a pT3N1b papillary thyroid carcinoma. Three years after initial surgery (total thyroidectomy and therapeutic central and lateral neck dissection) and RAI, chest CT showed two lung micrometastases, which remained stable over time. Three years later, neck ultrasound revealed lateral neck metastases, treated surgically at an outside institution. Thyroglobulin (Tg) remained elevated postoperatively, however, with a negative post-RAI whole body scan. Four years later, increasing Tg lead to the diagnosis of three ¹⁸FDG-PET-CT-positive and fine needle aspiration biopsy positive metastases in the central and lateral neck compartments. The size of the lung metastases remained stable <1 cm. Surgery was performed at our institution with complete macroscopic resection of the neck metastases, which required sacrificing the right internal jugular vein and the right recurrent nerve and shaving of the esophageal muscle. At 10 months, a new 1 cm metastasis in the middle mediastinum was detected on ¹⁸FDG-PET-CT with stable lung metastases. This case illustrates several risk factors for persistent/recurrent and RAI-refractory disease. Surgical treatment may be warranted for resectable disease in the neck if preoperative imaging is in favor of complete resection without major morbidity, due to the relatively long life expectancy of patients with differentiated thyroid cancer.