How does cholesteatoma develop in the middle ear?

A cholesteatoma develops in the middle ear as an ingrowth of skin originating from the outer-ear canal. This skin tissue forms a cyst within the middle-ear cavity.1

As the cyst becomes infected, it enlarges in a slow but progressive manner. This growth process gradually erodes the surrounding bone. If left untreated, the cyst can expand until it reaches critical structures, including the brain cavity, the facial nerve, or the semicircular canals of the inner ear. Such progression can lead to severe complications, such as meningitis, brain abscess, facial nerve paralysis, or inner-ear infections that may result in total deafness.1

Due to these risks, medical professionals typically diagnose the condition through examination of the tympanic membrane and X-ray studies, followed by surgical removal to prevent further damage.1