Inverted papilloma of the nasal vault and paranasal sinuses: spectrum of CT findings.

Inverted papilloma is a benign epithelial neoplasm that arises within the nasal vault and, less commonly, in the paranasal sinuses. It is relatively uncommon, accounting for less than 4% of mucosal tumors in this region. The tumor is characterized by a high recurrence rate (emphasizing the importance of accurate tumor mapping and total tumor extirpation), associated epithelial malignant tumors (5-8%), and bone destruction. The CT appearance of inverted papilloma is variable and non-specific. Nonetheless, inverted papilloma is the most likely diagnosis when a unilateral mass in the nasal vault, producing benign bony changes, extends centrifugally into the maxillary and ethmoidal sinuses and through the nasal choana into the nasopharynx in an elderly patient with chronic nasal obstruction. The purpose of this essay is to illustrate the CT features of inverted papilloma.