Description and clinical importance of the lymphatics of the vocal fold.

Findings of the presence of lymphatics in the subepithelial connective tissue layer of the true vocal cord range from the statement that lymphatics are absent to the observation that a dense lymphatic network exists. This is undoubtedly a result of the different methods of examination. The entire extent of a lymphatic system can be shown by either an enzyme histochemical demonstration of the 5'-nucleotidase activity in the lymphatics, or electron microscopy, which is more elaborate. These two methods are used to describe a subepithelial lymphatic network of varying density in 80 human vocal folds, which--contrary a frequent assumption--is not interrupted in the area of the free margin of the true vocal cord. Under the squamous epithelium, the density of the lymphatic system, which is very high in the arytenoid region, decreases continuously toward the anterior portion of the true vocal cord. It is exactly in the region in which the lymphatic system is the sparsest that almost all cancers of the true vocal cord develop. This finding is highly significant, in view of the low incidence of lymphogenous metastasis formation in T1-glottic cancers.