ct study of the temporal bones was performed on multislice brilliance ct scanner. 1. external auditory canals are normal. 2. soft tissue attentuating lesion filling the entire left middle ear tympanic cavity, aditous and antrum and mastoid antrum with erosions ta left scutum, body of malleous, long and shord processes of incus. 3. complete loss of left mastoid air cells with sclerosis. 4. middle ear cavity ossicular chain and mastoid air cells are normal on right side. 5. cochlea , vestibule and semicircular canals are normal intermal auditory canals are normal. 6. facial nerve canals are normal impression. 1. features are suggetive of CSOm with cholesteatoma at left middle ear tympanic cavity, aditous and antrum and maptoid antrum with erosions of middle ear ossicles and left scutum. 2.chrnoic sclerosing left mastoiditis