Thyroid nodules occurring in old age and young age are highly likely to be cancerous tumors, especially in men. The likelihood of malignancy rises with accelerated tumor growth and localized invasion, but these symptoms are rare. There is an increased risk of cancer in families with medullary thyroid carcinoma, papillary carcinoma and familial polyposis (Gardner’s syndrome). Cancer is found more often in patients with firm, isolated nodules than in patients with multiple nodules. Adhesive fixation of nodules to nearby structures, vocal cord paralysis, and enlarged lymph nodes are likewise associated with an increased risk of malignancy.