Inverted papillomas are often indistinguishable from polyps radiographically. Papillomas that occur in a characteristic location may be identifiable, such as inverted papillomas that arise in the medial wall of the antrum and extend both into the antrum and the nasal cavity. A lobular (“cerebriform”) configuration is also suggestive of papilloma. Bony sclerosis and osteoneogenesis are frequently present at the site of attachment of inverted papillomas.
Inverted papilloma. Axial CT shows a lobular mass (asterisk) centered in the lateral nasal wall, with extension into both the nasal cavity and the maxillary sinus. The location, configuration, and central calcifications are all indicative of inverted papilloma.