摘要
Congenital cholesteatoma（CC）is a rarely seen benign tumor of the temporal bone. There are five general sites of extradural occurrence: the middle ear, external auditory meatus, mastoid, squamous portion and the petrous apex of the temporal bone. CC grows slowly and presents no symptoms at the early stage. Delayed and mis-diagnosis are common with this condition. Case report A 10-year-old boy presented with a 3-month history of hearing loss on right side. There was no history of otorrhea, facial palsy, previous otological procedures or trauma. Otoscopy revealed a bulging posterosuperior quadrant in the otherwise intact right tympanic membrane （Fig.1）. Pure tone audiometry showed an average threshold of 51 dB for 500, 1000, 2000 and 4000Hz, with a 40 dB air-bone gap, suggesting a moderate conductive hearing loss（Fig.4）. CT scan of the temporal bone showed an isolated soft tissue density lesion in the middle ear（Fig.2）.
