Non-toxic multinodular goitres

Thyroid nodules are common, especially in women, and most are benign (-7% are malignant). Recent research into the pathogenesis of simple, nodular goitres has shown a strong genetic predisposition which interacts with environmental factors such as dietary goitrogens, smoking, and iodine deficiency. Most benign nodules in multinodular goitres seem to result from genetic mutations which result in monoclonal overgrowth of thyrocytes with a growth advantage but a range of function, resulting in cold, warm or hot nodules seen on isotopic thyroid scans. In most mutations thyrocyte growth appears to be autonomous and independent of thyrotrophin stimulation. Management options for multinodular goitres include regular clinical and functional assessment only (for small euthyroid goitres), surgery and radio-iodine. Suppression of thyrotrophin with thyroxine therapy is often ineffective, must be lifelong, and is associated with serious potential hazards (osteoporosis and an increased risk of atrial fibrillation). Total thyroidectomy eilminates the high risk of recurrent goitre (up to 60% at 10 years), but requires a practiced surgeon. Radio-iodine therapy (2.2 GBq, 60 mCi, single or fractionated dose) is effective in safely reducing goitre size (by ∼50%) and relieving obstructive symptoms. Fine-needle aspiration cytological evaluation is essential for all apparently single nodules and for dominant nodules.