NEW BARRIERS TO VENTRICULAR INVASION IN PARAGLOTTIC LARYNGEAL-CANCER

Background. Anatomic barriers to the spread of laryngeal cancer includ e the conus elasticus, the quadrangular membrane, and the thyroid cart ilage. It has been speculated that an elastic barrier surrounds and pr otects the ventricle. Methods. The authors studied the microanatomic p atterns of spread of 17 cases of patients who had laryngeal cancer wit h paraglottic disease and confirmed their findings by examining normal autopsy specimens. Results. Five patients of the seventeen cases show ed no ventricular mucosal involvement despite extensive paraglottic di sease. Both an inner, central, subepithelial periventricular elastic b arrier, and a more peripheral periventricular elastic membrane barrier were identified; the latter was in continuity with the conus elasticu s and quadrangular membrane. Conclusions. Two weak fibroelastic barrie rs surround the ventricle. The outer, peripheral, fibroelastic membran e is contiguous with the conus elasticus and the quadrangular membrane . Therefore, ventricular involvement is not a sensitive indicator of p araglottic spread. Squamous cell cancer may grow around the periventri cular barriers to involve both the true and false cords but may spare the ventricle. The prognostic significance of the violation or preserv ation of the periventricular elastic barriers is unknown.