[Two cases of carotid sheath ectopic thyroid carcinoma]

Ectopic thyroid tissue is resulting from developmental defects at early stages of thyroid gland embryogenesis. It can be found in many sites,including the tongue, pharynx, hyoid and throat. Ectopic thyroid tissue may also be involved in the same pathological processes as normal, or hotopic thyroid gland. These processes include tumors, inflammation and hyperplasia. They can cancerization, and the treatment of ectopic thyroid carcinoma is also controversial. The appearance of such tissue in rare locations may lead to diagnostic and therapeutic dilemmas.