CT Evaluation of Nasal Cavity Masses: Differential Diagnosis between Nasal Polyps and Their Mimics

ABSTRACT

PURPOSE: The purposes of this article are to identify CT findings distinguishing nasal polyps, that are the most common cause of the nasal polypiod lesions, from other nasal cavity masses and to identify differential points between benign and malignant masses of nasal cavity. MATERIALS AND METHODS: We classified 567 cases of pathologically proved nasal cavity masses into 4 different groups on CT according to the sites of origin and surrounding bone changes. RESULT: The nasal polyps were the most common cause of nasal cavity masses(515/567). Group I had a high diagnostic specificity for the nasal polyps (513/515, 99.6%) although inverted papilloma (8/522) and malignant melanoma(1/522) showed similar CT appearances. The representitive nasal mass of Group Ila was the inverted papilloma (15/24, 66.5% of the inverted papilloma). Group III pattern was seen in 3 cases of benign minor salivary gland tumor and 2 cases of pyogenic granuloma. Group IV suggested malignancy and thus was mostly observed in malignant tumors except I case of inverted papilloma and 1 case of granulomatous necrosis. CONCLUSION: The differential diagnosis between nasal polyps and the other nasal cavity masses is possible by characteristic bone changes and their sites of origin revealed on CT. In addition, it is possible to differentiate malignant masses from benign in most cases.