Which type of thyroid nodules are typically more likely to be malignant?

Cold nodules are typically more likely to be malignant compared to hot nodules. This is an important differentiation in the context of thyroid nodules. Cold nodules are those that do not take up radioactive iodine during imaging tests; their lack of iodine uptake suggests they may not be functioning normally. This abnormality raises the suspicion for malignancy.

On the other hand, hot nodules are those that take up radioactive iodine and are typically hyperfunctioning. These nodules are more frequently benign and often indicative of conditions like toxic adenoma or hyperthyroidism. The high level of activity in hot nodules typically correlates with benign pathology.

In clinical practice, the characterization of thyroid nodules as cold or hot is crucial for risk stratification and management decisions, with cold nodules warranting further investigation due to their higher association with cancer.