Pediatric upper airway obstruction due to ectopic thyroid: classification and case reports.

Few clinical situations can be as frightening, challenging, and as rewarding as stabilizing the airway of a child. Most causes of pediatric upper airway obstruction are well recognized, often discussed in the literature, and commonly encountered in practice. However, ectopic thyroid (i.e., thyroid tissue found in places other than its normal location) may be an unusual cause of pediatric upper airway obstruction with which the clinician may not be familiar. The resulting airway obstruction may be slow or rapid in onset, total or partial, and the relationship of the thyroid to the airway may be clear or obscure. Two cases of obstructing ectopic thyroid are presented which demonstrate the spectrum within which this form of airway obstruction may occur. One case is the first reported example in the English literature of pediatric intratracheal thyroid. A review of the literature is also presented. Four types of ectopic thyroid (lingual, sublingual, thyroglossal, and intralaryngotracheal) are illustrated and discussed in relation to their effect upon the pediatric upper airway. The authors also review the developmental anatomy of the thyroid and present two major theories regarding the development of intralaryngotracheal thyroid. The possible etiologies of the other ectopic forms are also discussed.