Malignant transformation of nasal polyp. Case report.

Malignant transformation of nasal polyps is believed to be very rare. A 49-year-old man had suffered from nasal polyposis and visited the hospital complaining of nasal obstruction and a huge nasal polyp in the right nostril. Histologic findings showed squamous cell carcinoma with microinvasion on the surface of the polyp and no invasion of carcinoma in the stalk. Simultaneously, malignant transformation of a small polyp was found in the left nasal cavity. Clinical and histologic findings are discussed.