en Oncology Oncology Original Research Original Research The authors used high-resolution computed tomography (HRCT) for studying 52 congenitally malformed ears in 45 children between five and 10 years of age. In six children the malformations were bilateral. The malformations clinically manifested as microtia, atresia of the external auditory canal and conductive deafness. Analyzing anatomical details and pathological changes on HRCT axial sections the authors established three groups of malformations. In the first group, auditory assicles were malformed in almost all cases, in the second group besides deformed auditory ossicles in majority of cases, the mastoid was apneumatised, and in the third group there were malformed auditory ossicles and the mastoids were apneumatised and in more than half of cases cavum tympani was malformed or filled with mesenchyme. These features have great importance in surgical reconstruction of congenital middle ear malformations. 105 109 http://mjiri.iums.ac.ir/browse.php?a_code=A-10-298-813&slc_lang=en&sid=1 D SAVIC 20031947532846006723 20031947532846006723 No From the Clinic of Otorhinolaryngology, University Clinical Center A JASOVIC 20031947532846006724 20031947532846006724 Yes From the Institute of Oncology and Radiology, Pasterova 14, 1100 Belgrade, Yugoslavia. D DJERIC 20031947532846006725 20031947532846006725 No From the Clinic of Otorhinolaryngology, University Clinical Center N MITROVIC 20031947532846006726 20031947532846006726 No From the Institute of Oncology and Radiology, Pasterova 14, 1100 Belgrade, Yugoslavia.