A cyst in the middle ear.

A cholesteatoma is a rare cyst in the middle ear. This cyst can happen because of a tear in the thin tissue between the ear canal and the middle ear, also known as a ruptured eardrum. The tear allows skin cells to enter the middle ear and make a cyst.

The cyst can become infected and damage bones in the middle ear. Damaged bones can affect hearing.

Antibiotic eardrops might help. Surgery is often needed.