Sinonasal Inverted Papilloma—Relevance of Radiological Anatomy in Disease Recurrence

Objective To describe the radiological anatomy of patients with inverted papilloma (IP) and to evaluate the association between radiological findings and disease recurrence. Methods Retrospective observational study of patients with inverted papilloma who underwent surgery between January 2010 and December 2019. Patients were grouped as primary and recurrent cases, and later at follow‐up, depending on disease status, they were subcategorized into ‘primary with no recurrence’ (PnR), ‘primary with recurrence’ (PwR), ‘recurrent with no further recurrence’ (RnR) and ‘recurrent with further recurrence’ (RwR) groups. Radiological and surgical data were collected and analysed. Results Among the 117 patients, zygomatic recess was anatomically the most prevalent maxillary recess. Palatonasal was the most commonly affected recess in both primary and recurrent groups. Within the maxillary sinus, the most common sites of recurrence were the lateral wall and floor. Anterior ethmoid ( p = 0.047), frontal recess ( p = 0.017) and frontal sinus ( p = 0.026) showed significantly higher radiological involvement in recurrent cases compared to primary cases. Among the recurrent cases, involvement of posterior ethmoid ( p = 0.030), frontal recess ( p = 0.017), intraorbital extraconal compartment ( p = 0.036) and Krouse stage T4 ( p = 0.002) were significantly higher in those with repeated disease recurrence (RwR). Conclusion In recurrent IP, predictors of repeated recurrence include the site of initial recurrence being the frontal recess/sinus region, involvement of the posterior ethmoid, frontal recess and intraorbital extraconal compartment, and Krouse stage T4 at the time of diagnosis.