Cholesteatoma of the middle ear mastoid is a common disease in otology. Although cholesteatoma is not a tumor, it is locally destructive and prone to recurrence after surgery. Its main features are; foul-smelling pus, progressive hearing loss, and in severe cases, intracranial and extracranial complications such as meningitis, brain abscess, sigmoid sinus thrombophlebitis, retroauricular subperiosteal abscess, facial palsy, and even life-threatening. Once cholesteatoma formation is detected, early consultation and treatment measures should be taken. The occurrence of cholesteatoma is complex and can be either congenital or acquired. Congenital cholesteatomas are most often seen in children or adolescents, with gradual hearing loss and pus flowing from the ear when accompanied by infection. In acquired cholesteatoma, some patients have a history of secretory otitis media, and although the symptoms of ear congestion improve later, hearing does not recover, or even declines progressively, and the eardrum becomes invaginated, gradually forming a cholesteatoma. Cholesteatoma may also develop in patients with marginal or even central perforation of the tympanic membrane, and destruction of the middle ear mastoid bone (including the auditory bone) may occur on CT examination.