Figure 6.

(a) Images of thyrothymic thyroid rests: Shows bits or deposits of ectopic thyroid tissue, which lie below the thyroid gland level and arise in the thyrothymic tract. They may be variable in size; unilateral (a) or may be bilateral, although most of them may be very small. These may occur either as entirely separate nodules (b) these ectopic thyroid tissue may occur as bilateral or unilateral prolongations (c and d) arising from either one or both thyroid lobes (arrow) and might be of clinical importance during thyroid or parathyroid surgery. They tend to be attached by thin sheets of thyroid or fibrous tissue to the main body of thyroid gland, but 20% have no attachment at all and can migrate to mediastinum and present as intra thoracic mass