Final answer:
Typically, thyroid nodules greater than 1 cm with suspicious features, and specifically those between 1-4 cm, should be evaluated with Fine Needle Aspiration. For nodules less than 1 cm, FNA is usually not indicated unless there are highly suspicious features or lymph node involvement.
Step-by-step explanation:
The size of a thyroid nodule that typically requires a Fine Needle Aspiration (FNA) can vary, based on multiple factors including the presence of ultrasound features suggestive of malignancy and the patient's clinical risk factors. Generally, the current guidelines suggest that nodules greater than 1 cm in size showing suspicious characteristics should be considered for FNA, especially those between 1-4 cm. Nodules less than 1 cm typically do not require FNA unless they exhibit highly suspicious features or there is evidence of lymph node involvement. For nodules greater than 4 cm, FNA is often indicated, but decisions may also be influenced by clinical judgment and specific attributes of the nodule.