Graves' disease in a mediastinal mass presenting after total thyroidectomy for nontoxic multinodular goiter: a case report.

Background: Thyrotoxicosis after total thyroidectomy is mostly iatrogenic. Rarely, a hyperfunctional thyroid remnant or ectopic tissue may be the cause. There are few cases of Graves' disease arising from thyroid tissue located in the mediastinum and none in which Graves' disease was diagnosed only after surgery.