Ectopic thyroid tissue implantation associated with hyperthyroidism after endoscopic thyroidectomy: a case report.

BACKGROUND: Needle track implantation is a rare complication of endoscopic surgery. This appears to be the first reported case of ectopic thyroid tissue implantation in the anterior chest wall following endoscopic thyroidectomy, accompanied by hyperthyroidism. CASE DESCRIPTION: The patient underwent endoscopic thyroidectomy for a 5 cm left thyroid adenoma. Within one year postoperatively, she noted a chest wall mass extending from the left subclavicular region to the line connecting the left nipple, accompanied by hyperthyroidism. Following treatment with antithyroid drugs, thyroid function was well controlled and the chest wall mass ceased to enlarge. Pathological examination confirmed the left anterior chest wall mass as ectopic thyroid tissue. CONCLUSIONS: This case highlights not only the risk of tissue fragment dissemination following endoscopic thyroidectomy but also indicates that ectopic thyroid tissue, under favorable microenvironmental conditions, can preserve follicular structure and may be involved in metabolic activity.