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. The tumor is slow growing, and many patients will present with cervical lymph node metastases. Follicular carcinoma account for up to one quarter of thyroid malignancies. It is also slow growing and usually asymptomatic. It usually presents in the 5 th and 6 th decades of life, is more common in females, and may spread both via lymphatics and in the blood.