Histochemistry of normal middle ear mucosa.

Mucosal biopsy specimens were taken from the middle ear in 19 patients with otosclerosis and stained by Alcan blue and PAS. They were also stained for hydrolytic and oxidative enzymes. In additon, 11 temporal bones from patients without any previous ear disease were serially sectioned for mucopolysaccharides. In otosclerosis, both acid and neutral mucopolysaccharides were present in the mucosa, but not to the same extent as in the temporal bone specimens. Acid phosphatase, lactate malate dehydrogenases, and nonspecific esterase were demonstrated even in very thin epithelium, providing a potential basis for the appearance of these enzymes in large amounts in various inflammatory middle ear diseases.