Congenital cholesteatoma is now diagnosed earlier than heretofore. The age at presentation in the most recent series is 1 to 4 years, as opposed to 20 years in the series reported by House and Sheehy (3, 4, 5) in 1980. The characteristic appearance is that of a white mass in the anterior superior quadrant of the middle ear behind an intact tympanic membrane (Figs. 25.1 and 25.2).

An apparent increase in the reported incidence of congenital cholesteatoma in recent years may be due, in part, to improvement in diagnostic capabilities, including halogen illumination for otoscopy, pneumatic otoscopy, and routine hearing screening. However, most congenital cholesteatomas present to the otolaryngologist in the setting of a refractory serous otitis media or an abnormality thought to be in the tympanic membrane. The lesion may also be discovered incidentally at the time of a myringotomy.

The incidence of otitis media in patients with congenital cholesteatoma is the same as in the general population. However, a diagnosis of congenital cholesteatoma should be considered in any patient with unilateral middle ear effusion or conductive hearing loss. Although a congenital cholesteatoma limited to the anterior superior quadrant of the middle ear may be entirely asymptomatic, it may cause a unilateral middle ear effusion due to obstruction of the eustachian tube.

Posterior extension toward the incudostapedial joint may cause destruction of the lenticular process of the incus and capitulum of the stapes. Eventually the superstructure of the stapes will be destroyed while the footplate usually remains intact. Progressive growth of congenital cholesteatoma into the attic, aditus ad antrum, and mastoid is similar to acquired middle ear cholesteatoma. At this stage it almost certainly would be complicated by infection or rupture of the tympanic membrane, making it difficult to assume a congenital origin with any degree of certainty.

Aimi (6) in 1983 postulated that congenital cholesteatoma is caused by migration of ectoderm from the external canal into the middle ear at an early stage of embryonic life. Sobol et al. (7) presented the concept that recurrent otitis media may cause basal cell proliferation in the tympanic membrane, leading to a seemingly congenital cholesteatoma behind an intact tympanic membrane. Northrop and colleagues (8) have proposed that viable amniotic debris within the middle ear of neonates may cause congenital cholesteatoma. Michaels (9) in 1988 theorized that congenital cholesteatoma arises from an epidermoid rest in the developing middle ear. This “epidermoid formation” (4) is present in most fetal ears at the junction of the eustachian tube and middle ear near the tympanic ring until 32 weeks’ gestation. He postulated that congenital cholesteatoma is caused by persistence and growth of the epidermoid formation. This hypothesis is attractive and explains the propensity of congenital cholesteatoma to appear in the anterosuperior segment of the middle ear. However, conclusive proof awaits the discovery of a lesion of intermediate stage in a temporal bone. Lee et al. (10) in 1998 reinvestigated the role of the epidermoid formation in serial sections of fetal and neonatal temporal bones to assess its relationship to congenital cholesteatoma. Epidermoid formations were found in 88 (42%) of 211 temporal bones from 6 weeks’ gestation to 6 months postpartum. The site of the epidermoid formation was an average of 389 microns anterior to the anterior margin of the tympanic membrane. Several epidermoid formations were found on the medial surface of the anterosuperior tympanic membrane. Although the average diameter of an epidermoid formation was 242 microns, some were greater than 1,500 microns in diameter, which approximates the size of a small congenital cholesteatoma. These findings support the concept that the epidermoid formation is a precursor of the common form of closed type of congenital cholesteatoma seen in the anterior superior quadrant of the middle ear.