Prior radiation exposure or family history of thyroid malignancy point towards a nodule being malignant. The vocal cords should be evaluated, because vocal cord weakness or paralysis would also point towards a nodule being malignant. Thyroid function tests are less helpful in distinguishing a benign from malignant nodule. Radionucleotide scanning is done to differentiate hot from cold nodules. Hot nodules are those that take up increased amounts of the radionucleotide.
Cold nodules are more likely to be malignant.
A cold nodule is the most important finding on a thyroid scan. Ultrasound distinguishes cystic from solid nodules. Fine needle aspiration is performed on most palpable nodules, and can identify certain malignancies. Papillary carcinoma is the most common thyroid malignancy. Most patients are asymptomatic.