Acoustic neuroma is a benign tumor that usually arises from the Schwann cells of the vestibular nerve and in rare cases also from the Schwann cells of the cochlear nerve.
An inflammation of the ear canal (also otitis externa) is defined as a bacterial, fungal, or allergic inflammation of the skin and subcutis in the outer ear canal.
Cholesteatoma is a chronic, purulent inflammation of the middle ear caused by a proliferation of squamous epithelium from the outer auditory canal into the middle ear.