Inverted Papilloma

This is a case of an incidental inverted papilloma in an 86-year-old male with a history of a low-grade glioma. There is an expansile lesion centered near the region of the right middle meatus, and completely filling the right maxillary antrum. The mass is T1 isontense to skeletal muscle, T2 heterogeneously hyperintense with low ADC values and avid post contrast enhancement. The lesion displays curvilinear striations giving it a convoluted, cerebriform appearance on both the T2 weighted and postcontrast images. Differential diagnoses include solitary sinonasal polyp, sinonasal squamous cell carcinoma, or sinonasal polyposis. Degeneration into or coexistence with squamous cell carcinoma occurs in up to 10% of cases. Inverted papillomas typically arise along the lateral nasal wall, being centered at the middle meatus. The lesion may or may not extend into the right maxillary antrum.