Human Middle Ear Epithelium: An Ultrastructural and Cytochemical Study

IN CONTRAST to the hitherto prevailing opinion that the normal human middle ear lining consists of flat or cuboidal cells and lacks mucus secreting elements, Sade 1 found it to be a true mucosa that possesses cilia and secretes mucus. Secretory cells were also reported in the tympanic epithelium in dogs by Senturia et al, 2 and in guinea pigs by Lim et al. 3 Hussl and Lim 4 further distinguished three morphologically and cytochemically different types of secretory cells—dark granulated, intermediary, and goblet cells—in the transitional zone of the guinea pig middle ear mucosa. This study is concerned with the fine morphology and cytochemistry of the epithelium lining the normal human tympanic cavity. Material and Methods Biopsies from presumably normal middle ear mucosa were obtained from nine patients undergoing stapedectomy for otosclerosis and from one patient undergoing labyrinthectomy for Meniere's disease. All patients were adult, ranging from 28