The thyroid gland is found in the neck and corresponds to the 2-4 tracheal cartilages. It is rarely found in other sites and is termed ectopic thyroid tissue (ETT) once found. In this report, we present a case of a 19-year-old female who was diagnosed with ETT in the lumbar region and posterior mediastinal region after total thyroidectomy for a large dominant thyroid nodule. ETT has a unique presentation and physicians should be vigilant to diagnose it correctly and promptly to decrease morbidity associated with the disease.