Endocrine Abstracts

Total thyroidectomy is the preferred surgical procedure in patients with high-grade multinodular goiter. The necessity for long-term neck ultrasound (US) surveillance after thyroidectomy for benign diseases remains unclear as the risk of recurrence is very low. However, in a minority of patients a thyroid neoplasm could arise from very small thyroid remnants. We report a case of a 65-year-old female who underwent thyroidectomy for nontoxic multinodular goiter in 2013. Histological examination was consistent with benign nodular hyperplasia. Levothyroxine replacement therapy was started thereafter but regular US examination was not performed. Five years later the patient presented with newly developed persistent dysphonia and was diagnosed with vocal cord paralysis. The subsequent US neck imaging found a big hypoechoic nodule in the left thyroid bed with irregular shape, blurred margins infiltrating the trachea (EU-TIRADS 5). Lymph nodes with metastatic US features were detected in the left lateral compartment (level IV). Serum calcitonin was significantly elevated. Fine needle aspiration biopsy revealed cytological evidence of malignancy and the extremely elevated calcitonin in the cervical lymph nodes washout confirmed metastases from medullary thyroid cancer. The patient was referred to surgery but due to the local invasion complete tumor resection was not possible. Following surgery targeted therapy with tyrosine kinase inhibitors was initiated to prevent further disease progression. The clinical case suggests that aggressive thyroid malignancy can develop from microscopic tissue remnants several years after thyroidectomy. Ultrasound examination is a valuable tool in the long-term follow-up after thyroidectomy even for benign disorders.