Cholesteatoma is an abnormal skin growth that occurs in the middle ear behind the eardrum. It often develops as a result of repeated ear infections or poor eustachian tube function, leading to the accumulation of skin cells and other debris. Over time, this growth can expand and damage surrounding structures, including the bones of the middle ear. Symptoms of cholesteatoma may include hearing loss, ear pain, and drainage from the ear. If left untreated, it can lead to serious complications, such as hearing loss or infections that spread to nearby areas, including the brain. Treatment typically involves surgery to remove the growth and repair any damage.