Computed tomography of the thyroid attenuation (80–100 Hounsfield Units). The presence of thyroiditis can be suggested by a diffusely enlarged and hypo-attenuating (around 45 Hounsfield Units) thyroid gland. This is probably due to follicular cell destruction and reduced thyroid iodine concentration. Marked homogenous enhancement is typically expected. Therefore, moderate thyroid enhancement in a case of thyroiditis suggests a diffuse inflammatory process. It is essential to clinically correlate this with a thyroid function test and serum autoantibody levels. During embryogenesis, the bi-lobed thyroid migrates inferiorly from the foramen cecum of the tongue to the lower neck. Initially, the thyroid primordium passes anterior to the primordial hyoid
Thyroid dysgenesis arises from remnants of the thyroglossal duct, and may appear anywhere along its original length. Accessory thyroid tissue may be functional, but is generally insufficient for normal function if the main thyroid gland is entirely removed. Lingual thyroid is 4-7 times more common in females, with symptoms developing during puberty, pregnancy or menopause. Lingual thyroid may be asymptomatic, or give symptoms such as dysphagia (difficulty swallowing), dysphonia (difficulty talking) and dyspnea (difficulty breathing). Thyroid dysgenesis Thyroid dysgenesis or thyroid agenesis is a cause of congenital hypothyroidism where the thyroid is missing, ectopic, or severely underdeveloped. It should not be confused