Thyroid carcinoma presenting as a tracheal tumor. Case report and literature review with reflections on pathogenesis.

Ectopic thyroid tissue within the submucosa of the trachea is a rare cause of upper airway obstruction. Most case reports in the literature record examples of intratracheal goiter with only occasional reports of neoplasms arising from such thyroid rests. This report describes a young female patient with a malignant tumor, thought to be primary in the trachea, treated first by radiotherapy and eventually successfully surgically excised. The surgical resection required total thyroidectomy with partial laryngectomy and major tracheal resection, and provided an excellent functional result. The clinical history, laboratory findings and histologic sections strongly suggest that this tumor arose within the tracheal submucosa from ectopic thyroid tissue. In a series of 250 serially sectioned larynges, such ectopic thyroid tissue has been identified in only two patients.