Sinonasal papillomas (SPs) are a group of uncommon benign, but biologically distinct, neoplasms. They can be locally aggressive with potential to undergo malignant transformation ( “carcinoma ex-sinonasal papilloma”), especially inverted sinonasal papillomas (ISPs) and oncocytic sinonasal papillomas (OSPs),  but also rarely exophytic sinonasal papillomas (ESPs).  Genetically, most have EGFR mutations and mutually exclusive human papillomavirus (HPV) infection in inverted SPs, all oncocytic SPs have KRAS mutations and exophytic SPs are associated with low-risk HPV infection. ¹