en Otorhinolaryngology Otorhinolaryngology Original Research Original Research This study investigated the presence of mast cells in inflammatory aural polyps using light microscopy. The number of mast cells was increased in all examined cases and varied from 2.33 to 41.54 per mm2• The cells were located most commonly around small blood vessels. Occurrence of mast cells was not different in various types of polyps, but their density was severely increased in active inflamed polypous tissue. These findings suggest that mast cells may be a contributory factor in the pathogenesis of middle ear inflammatory processes. Mast cells, Inflammatory aural polyps, Pathogenesis. 257 259 http://mjiri.iums.ac.ir/browse.php?a_code=A-10-298-368&slc_lang=en&sid=1 DRAGO SLAVA R. DJERICJ 20031947532846004531 20031947532846004531 Yes From the Institute of Otorhinolaryngology and Maxillofacial Surgery, Pasterova 2, Belgrade 11000, Yugoslavia