A 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 a malfunctioning Eustachian tube, which can lead 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 a cholesteatoma may include hearing loss, ear pain, and drainage from the ear. If left untreated, it can lead to serious complications, such as infection or damage to nearby structures, including the inner ear and brain. Treatment typically involves surgery to remove the growth and restore normal ear function.