Chae-Seo Rhee

Objectives This study aimed to evaluate the characteristics and treatment outcomes of inverted papillomas involving the frontal sinus. Methods Patients treated for inverted papilloma involving the frontal sinus between 2003 and 2020 were reviewed. Tumors were classified based on their extent (Extent 1: partially encroaching on the frontal sinus; Extent 2: completely filling the frontal sinus; Extent 3: eroding bony borders beyond the frontal sinus) and site of origin (Origin 1: originating outside the frontal sinus and prolapsing into the frontal sinus; Origin 2: originating from the frontal sinus walls medial to the vertical plane of the lamina papyracea; Origin 3: originating from the frontal sinus walls lateral to the vertical plane of the lamina papyracea). Treatment outcomes including tumor recurrence and patency of the frontal recess were analyzed according to tumor characteristics and surgical treatment modalities. Results A total of 49 surgical cases were analyzed. Extent 1 were the most common type ( n = 27), followed by Extent 2 ( n = 15), and Extent 3 ( n = 7). The most common sites of origin were Origin 1 ( n = 23), followed by Origin 2 ( n = 15), and Origin 3 ( n = 11). Overall, there were nine recurrences (18.4%). Recurrence was not associated with tumor extent, whereas tumor origin, particularly Origin 3 was associated with higher recurrence; 1/23 (4.3%) for Origin 1, 3/15 (20.0%) for Origin 2, and 5/11 (45.5%) for Origin 3 (Log‐rank p < .001). Draf III frontal sinusotomy was associated with in the highest patency rate (84.6%) during the follow‐up. Conclusion The recurrence rate of frontal sinus inverted papilloma depends on tumor origin rather than the extent of the tumor. In particular, lesions originating from the frontal sinus lateral to the lamina papyracea recur frequently. Draf III frontal sinusotomy can achieve patent frontal recess allowing active surveillance. Level of Evidence IV