Acquired atrophy of the long process of the incus.

Various lesions can cause conductive hearing loss in a patient with a normal tympanic membrane. These include congenital ossicular anomaly, otosclerosis, and congenital or acquired ossicular fixation and discontinuity. We had an experience with a patient who presented with a conductive hearing loss in both ears, in which small pieces of the long process of the incus were absent and had been replaced with fibrous tissues in both ears. No other abnormalities, such as postinflammatory changes or fixation of the ossicles, were found. Because the long process of the incus undergoes remodeling through resorption and rebuilding throughout life, failure of the remodeling or impaired vascular supply to the long process of the incus may have been the cause of the conductive hearing loss in this patient.