Clinical Variants, Rates of Post-Operative Recurrence and Malignant Transformation of Sino-Nasal Inverted Papilloma

Background: Inverted Papilloma (IP) is the most common benign neoplasms arising from the mucosal lining of the of the Sino-Nasal tract with single or multifocal attachment sites. The high propensity to recur, local aggressive behavior and possibility of malignant transformation attract considerable interest. Objective: To assess the factors affecting Sino-nasal IP, malignant transformation rate, and post-operative recurrence rate. Methods: A retrospective study was carried out on all cases diagnosed as Sino-Nasal Papilloma between January 2010 and December 2020 at Salmaniya Medical Complex, Bahrain. Data gathered from medical records were analyzed using SPSS. A total of 49 Sino-Nasal Papilloma cases were recorded of which 37 were IP. Factors affecting Sino-Nasal IPs are presented. Results: Sino-Nasal IP was recorded in 37 cases, composed of 28 males and 9 females with first presentation average age of 45.86 years. These involved 20 cases in the left side, 14 in the right side and 3 were bilateral. Recurrence in males and females was found to be 35.7% and 33%, respectively, with an average of 12.6 months. The symptoms include nasal blockage (97.3%), epistaxis and postnasal drip (13.5% each), headache (8.1%) and hyposmia and rhinorrhea (5.4%, each). The main recurrence was at stage T2 (60.5%), while in smokers (26.7%) and non-smokers (50%). Malignant transformation occurred in one patient only (2.6%). Conclusion: IP is the most common type of SNP with male predominance. The recurrence rate is high with an average of a year and the malignant transformation occurred in 2.6 % of the cases.