[Metaplastic ossification in nasal polyp].

Metaplasia is the production by cells of a kind of tissue other than that corresponding to their lineage, ie it represents the conversion of one tissue into another. Bony metaplasia has frequently been described in polyps of the gastrointestinal tract. In nasal polyposis it is an extremely uncommon finding. We describe the case of a 42 year-old female presenting nasal obstruction due to a unilateral nasal tumour. She was operated on by means of endoscopic sinonasal surgery and the definitive diagnosis was nasal polyposis with areas of bony metaplasia.