Perić A, et al. - In this retrospective analysis of prospectively collected data, researchers assessed the presence of epithelial squamous metaplasia and dysplasia in ethmoidal nasal polyps (NPs), nonneoplastic, chronic inflammatory outgrowths of the respiratory mucosa that usually occur bilaterally from the middle meatus and ethmoid sinus. Two hundred twelve patients (aged 18 to 72 years) with NP undergoing endoscopic ethmoidectomy were included in the study. According to findings, epithelial atypia signs have been discovered in 20.7% of NP patients, but the "true" epithelial dysplasia characteristic appears to be an exceptionally rare histological manifestation in NPs. The results suggest that aspirin sensitivity and occupational exposure to various noxious chemicals are associated with epithelial atypia in NPs. Although extremely rare, occasional epithelial dysplasia may be noted in NPs, a possibly useful fact for both rhinologists and pathologists.