Thyroid dysgenesis thyroid gland may be located anywhere along the path of the descent of the thyroid during its embryological development, although it is most commonly located at the base of the tongue, just posterior to the foramen cecum of the tongue. In this location, an aberrant or ectopic thyroid gland is known as a "lingual thyroid". If the thyroid fails to descend to even higher degree, then the resulting final resting point of the thyroid gland may be high in the neck, such as just below the hyoid bone. Parts of ectopic thyroid tissue ("accessory thyroid tissue") can also occur, and
Computed tomography of the thyroid of thyroid carcinomas. Differentiated thyroid carcinomas (DTCs) originate from follicular epithelial cells and encompass PTCs and follicular thyroid carcinomas, including the Hurthle cell variant of follicular carcinoma. DTCs have an excellent prognosis and fortunately represent the majority of thyroid carcinomas. PTCs and follicular thyroid carcinomas represent 88 % and 8 %, respectively, of all thyroid malignancies. Medullary thyroid carcinoma arises from neuroendocrine C-cells and has a good prognosis. Anaplastic carcinoma is an aggressive undifferentiated tumour that usually affects the elderly and tends to have a worse prognosis. Surgery is the primary mode of treatment for DTCs. Post total thyroidectomy radioactive