Abstract
The congenital cholesteatoma in the tympanic cavity has two types ; one is the closed type composed of a keratotic cyst and the other is the open type, wherein wide flat surface of epidermis forms part of the middle ear mucosa. The purpose of this paper is to compare clinical characteristics between two types of congenital cholesteatoma.
At an early stage, the closed type which is usually asymptomatic, is identified accidentally as a globular whitish mass through a normal tympanic membrane. It is found in the anterior-superior quadrant in the majority of these cases. The small anterior-superior cholesteatoma which has usually intact ossicles mainly originated from the tendon of the tensor tympani muscle or the medial surface of the malleus. The advanced cholesteatoma which is presented aural symptoms is found in the posterior-superior quadrant, and has ossicular damage.
On the other hand, the open type cholesteatoma has normal appearing tympanic membrane, so that it is found accidentally by an exploratory tympanotomy under a diagnosis of conductive hearing loss preoperatively. This is the reason why the open type cholesteatoma is usually associated with anomalies of the ossicles. The open type cholesteatoma seems not to grow and to remain silent due to evacuation of desquamated keratotic debris via the Eustachian tube until it is affected by infection or surgical stimulus. When the open type cholesteatoma is found during tympanotomy it is necessary to remove it completely.
