RESUMEN
BACKGROUND AND OBJECTIVES: The epithelium, basement membrane zone (BMZ) and superficial layer of lamina propria (SLLP) in the vocal fold possess similar mechanical properties and behave as one single tissue, which is commonly referred to as the "cover". The purpose of this study is to elucidate the ultra structural and histopathological changes and differences in the cover of benign laryngeal lesions, and also to investigate the pathogenetic response. MATERIALS AND METHOD: The cover of the vocal fold in vocal nodule, polyp and Reinke's edema was investigated on 87 patients. Immunohistochemical analysis was performed with monoclonal antibodies directed against collagen type III and VII for identification of SLLP and anchoring fiber. Control specimens were obtained from 10 uninvolved side vocal fold in the laryngeal specimen after total laryngectomy. RESULTS: One type of injury in the cover was due to a little or no change of SLLP, which was seen more often in vocal nodules. The second type of pathologic finding shows disorganized anchoring fiber and extensive interstitial injury, which was seen more often in vocal polyp. The third type shows injury in the anchoring fiber and sparse distribution of collagen type III in SLLP, which was the main finding in Reinka's edema. These findings lead us to understand the pathogenesis of the disease that developed as different entities. CONCLUSION: We conclude that collagens in BMZ and SLLP are the structures that seem to provide the pathogenetic portion of benign laryngeal diseases which develop from the same phonotrauma into clinically different disease entities.