HISTOPATHOLOGIC FUNDAMENTALS OF ACQUIRED LARYNGEAL STENOSIS

Acquired laryngeal stenosis is the most serious long-term complication of endotracheal intubation in children. Employing the whole-organ ser ial section technique, the sequence of histopathologic changes leading to stenosis was studied. Ulceration occurs when an endotracheal tube causes mechanical abrasion and/or induces pressure necrosis on the lar yngeal mucosa. Secondary healing of ulceration produces granulation ti ssue and subsequent fibrous scar tissue. Most exuberant granulation ti ssue resolves without sequelae, but some becomes firm, almost avascula r fibrous scar tissue. The accumulation of submucosal fibrous tissue m ay decrease the size of the glottic or subglottic lumen. Contraction o f scar tissue causes a distortion of glottic and subglottic laryngeal complex, leaving a reduced and irregularly shaped glottic and subglott ic lumen. Submucosal mucous gland hyperplasia directly reduces the inn er diameter of the airway. Finally, compromise of the laryngeal lumen may occur when the duct of a mucous gland is obstructed by scarring re sulting from intubation: mucus accumulates in the dilated duct, produc ing a ductal cyst.