Severe thyrotoxicosis caused by an ectopic intrathoracic goiter.

The case of a 71-year-old woman with severe thyrotoxicosis due to an ectopic multinodular intrathoracic goiter is described. Previously reported cases with intrathoracic ectopic thyroid tissue were either nontoxic, or, if thyrotoxic, were a direct continuation of the tissue of the normally located gland. This mass was proved to be of thyroid origin using Tc-99m sodium pertechnetate scanning.