[Clinicopathological study of squamous metaplasia in human laryngeal ventricles].

A clinicopathological study was performed to clarify the site of onset of primary cancer of the laryngeal ventricles using larynges resected from 22 individuals with no macroscopic lesions in the laryngeal ventricle, and the following results were obtained. 1) Computer graphics were applied to the laryngeal ventricles based on serial sections, and their complex morphology was displayed. 2) Since the morphology of the laryngeal ventricle is complex, the degree of progression of squamous metaplasia differed considerably depending on the morphology of the laryngeal ventricle, even in the same larynx. According to our classification, the "depressed" part exhibited very highly progressive squamous metaplasia in the laryngeal ventricle, and this appeared to be important as a preliminary stage of carcinogenesis. 3) The "depressed" part of the laryngeal ventricle was distributed anteriorly and posteriorly in the ventricle, and this closely coincided with the clinically preferred site of onset of primary cancer of the laryngeal ventricle. On the other hand, the distribution of the "branching" and "separate" parts, with little squamous metaplasia, was mainly in the center of the laryngeal ventricle, which has a low rate of occurrence of primary cancer of the laryngeal ventricle. 4) The metaplastic area in the epithelial membrane of the laryngeal ventricles has previously been reported to be very narrow, but we found that the area was rather broad in some cases. Moreover, the metaplastic area was significantly broadened by smoking and alcohol drinking, demonstrating that the epithelial membrane of the laryngeal ventricles is influenced by these habits.