Cholesteatoma Cholesteatoma is a cyst of squamous epithelium which causes damage in the middle ear and mastoid. Rarely the cyst is congenital and may arise anywhere in the temporal bone. The cyst usually becomes infected with anaerobic organisms which produce a putrid otorrhea. The growth of the cyst derives from desquarnation into the cyst and erosion of adjacent bone from granulation tissue and bacterial enzymes. Destruction respects no boundaries, and complications include facial paralysis, conductive and sensorineural deafness, vertigo, meningitis, and brain abscess.
Treatment requires surgical removal or marsupialization by mastoidectomy.
Otosclerosis Otosclerosis, a common cause of conductive hearing loss in adults, is a hereditary disorder of bone metabolism. Typically patients are born with normal hearing and suffer gradual bilateral hearing loss beginning in young adulthood. It is more common in women and worsens during pregnancy. Abnormal bone develops at the anterior end of the oval window resulting in fixation of the stapes and a conductive hearing loss of 40-50 dB. Sometimes the same process affects the inner ear and causes a variable degree of sensorineural hearing loss. If the disease is bilateral, the Weber test may be normal.