Forgotten goiter is a rare occurrence (2 - 16% of retrosternal thyroid cases) that depicts recurrence of retrosternal thyroid mass due to growth of remnant thyroid tissue overlooked during an initial thyroidectomy. The patient is a 59-year female who presented with dyspnea and stridor 25 years after total thyroidectomy. She was diagnosed as having a mediastinal mass on radiographic imaging. There were only localized pressure symptoms due to mass effect. The mass was excised employing an extra-cervical approach and using a partial sternotomy. The profuse extension of thyroid tissue, adherent to vital structures in the thorax and the extra-cervical thyroidectomy was a novel experience. The mass was completely excised and the patient's symptoms alleviated after the surgery. The patient recovered without any complications and there was no recurrence at 1 year of follow-up.