AACE, AME, and ETA Guidelines
AACE, in collaboration with the AME and ETA, published guidelines for the diagnosis and management of thyroid nodules in 2010. They recommend biopsy of any solid and hypoechoic nodule larger than 1 cm in diameter. They further recommend that thyroid nodules of any size undergo biopsy if the patient has been exposed to irradiation, has a family history of medullary carcinoma or multiple endocrine neoplasia, or has previously undergone partial thyroidectomy for thyroid cancer or if an elevated calcitonin level is present. The AACE/AME/ETA guidelines recommend biopsy of nodules of any size with marked hypoechogenicity, irregular or microlobulated margins, a taller than wide configuration (anteroposterior dimension greater than transverse dimension), microcalcifications, or "chaotic arrangement of intranodular vascular images" or "chaotic intranodular vascular spots." These guidelines recommend biopsy independent of size if ultrasonography suggests the presence of metastatic lymph nodes or if extracapsular growth is noted in the nodule. They recommend biopsy of the solid component of all complex cystic nodules because of the risk of cystic papillary carcinoma. They further suggest that nodules that are "hot on scintigraphy" do not require biopsy.