Cholesteatoma

Skin cyst growing in the middle ear that erodes bone

Overview

A cholesteatoma is an abnormal growth of skin cells, keratinizing squamous epithelium, in the middle ear and mastoid. It is not a cancer, but it slowly expands and releases enzymes that erode surrounding bone, including the ossicles, and it can extend into the inner ear, the facial nerve canal, or toward the brain. Most cases are acquired, arising from retraction pockets of the eardrum associated with chronic Eustachian tube dysfunction or from perforations, while a congenital form appears behind an intact eardrum in children. Typical features are persistent foul smelling discharge from one ear and gradual hearing loss, sometimes with dizziness or facial weakness. Diagnosis is by otoscopy, often supported by CT or diffusion weighted MRI. Treatment is surgical, usually involving mastoidectomy, and follow up is long term because it can recur. Untreated, it can lead to complications including meningitis and brain abscess.