A cholesteatoma is an abnormal skin growth that can develop in the middle ear behind the eardrum. It often occurs as a result of repeated ear infections or a malfunctioning Eustachian tube, which can create a vacuum that pulls in 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 infections or damage to nearby structures, including the inner ear and brain. Treatment typically involves surgery to remove the growth and restore normal ear function.