Follicular Thyroid Tumors
Are tumors derived from the thyrocyte, the cellular unit of thyroid follicle. These tumors include benign adenomas, papillary and follicular carcinomas, two entities considered as differentiated carcinomas, and undifferentiated or anaplastic carcinomas.
Clinical thyroid nodules, which are the consequence of abnormal localized growth of the thyroid tissue, are detected in 4–7 % of the general population in an iodine sufficient area. The prevalence is higher in countries affected by moderate or severe iodine deficiency. Infraclinical nodules are even more common, depending on the techniques used for screening, and ultrasonography detects nodules in more than 50 % of women older than 60 years. About 5 % of thyroid nodules are malignant. The annual incidence of thyroid carcinoma, the most common malignancies of endocrine organs, ranges...