Cholesteatoma may look like a tumor, but it's actually a cyst, and it isn't cancerous. However, cholesteatoma can have affects on the body that are nearly as severe as cancer.
One of the problems that cholesteatoma is famous for is creating hearing loss. The cyst can eat away at bone and tissue that is associated with hearing, causing deafness.
Like cancer, cholesteatoma can also spread. If not removed, the cyst can eat its way into the brain and facial nerve, causing infection and facial paralysis.