Thyroid nodule is a discrete lesion within the thyroid gland that is radiologically distinct from the surrounding thyroid parenchyma. Thyroid nodules are common. They are discovered as an accidental finding by a patient, or as an incidental finding during a routine physical examination in 3 to 7 % or by a radiologic procedure: 67 % with ultrasonography (US) imaging, 15 % with computed tomography (CT) or magnetic resonance imaging (MRI) of the neck, and 1–2 % with fluorodeoxyglucose (FDG) positron emission tomography. Their clinical importance is primarily related to the need to exclude malignancy (4.0 to 6.5 percent of all thyroid nodules, assess for their functional status and any pressure symptoms caused by them.