cholesteatomas

Cholesteatomas are abnormal, keratinizing squamous epithelium–lined cysts or sacs that develop in the middle ear or temporal bone behind the tympanic membrane. They contain desquamated keratin debris and inflammatory secretions. Although they are called cholesteatomas, they are not true neoplasms; they behave as destructive lesions that can erode temporal bone and compromise nearby structures.

Cholesteatomas are classified as congenital or acquired. Congenital cholesteatoma arises from epithelial rests and is usually present without a history of ear disease. Acquired cholesteatomas are more common and often result from chronic otitis media; they are further described as tubotympanic type, arising within the middle ear and mastoid, or attic/pars flaccida type, associated with retraction pockets of the tympanic membrane.

Pathophysiology involves accumulation of keratin debris and inflammatory mediators that drive bone resorption. Enzymatic activity and pressure from the expanding sac contribute to erosion of the tympanic membrane, tympanic cavity, ossicles, and occasionally the labyrinth or skull base. This can lead to conductive hearing loss and, less commonly, sensorineural loss.

Clinical presentation typically includes persistent unilateral foul-smelling otorrhea and progressive hearing loss. Patients may report ear fullness, tinnitus, and, with extension, vertigo or facial nerve symptoms. Otoscopic examination may reveal a retraction pocket or a visible pearly or yellow mass behind an intact or perforated tympanic membrane.

Diagnosis relies on clinical suspicion supported by imaging. High-resolution CT of the temporal bone defines extent and bone erosion; MRI with diffusion-weighted imaging helps distinguish cholesteatoma from scar tissue or granulation. Treatment is surgical removal, with approaches including canal wall down or canal wall up mastoidectomy and tympanoplasty, depending on extent. Recurrence is possible, necessitating long-term audiologic and radiologic follow-up. Complications include ossicular destruction, intracranial or intratemporal extension, facial nerve palsy, meningitis, and brain abscess.