The basement membrane in diseases of the vocal cords: electron microscopy and immunomorphologic findings

The basement lamina of the epithelium of the true vocal cords of 34 inpatients suffering from chronic laryngitis, Reinke's oedema and squamous cell carcinoma have been investigated with the electron and immunofluorescence microscope. In chronic laryngitis, the lamina fibroreticularis is thickened (due to collagen type VII), corresponding to the clinical finding. In this layer mobile cells of the connective tissue can be found. In cases of Reinke's oedema it is the lamina densa which might be thickened. In this disease, also lamina densa-like material can protrude into the lamina fibroreticularis, and the number of anchoring filaments is increased. In squamous cell carcinoma we found the basement lamina irregularly arranged and folded. The lamina densa was always interrupted by numerous small gaps and in some areas the basement membrane could not be identified over a long distance. Lamina densa-like material was also found between the tumour cells within the epithelium. With the immunofluorescence microscope this material was proven as laminin, collagen type IV and heparan sulfate proteoglycan. Our investigation shows that malignant as well as benign lesions of the true vocal cords are characterised by distinct fine structural findings even concerning the basement lamina.