Endoscopic treatment of inverted papilloma attached in the frontal sinus/recess

Background: Inverted papilloma (IP) is a benign sinonasal tumour for which endoscopic surgery, with complete removal of the underlying and surrounding mucoperiosteum at the attachment site followed by drilling and/or coagulation of this area, is the treatment of choice. This can be challenging in the frontal sinus. Objectives: To report on the outcome of treatment for IPs involving the frontal sinus. To propose the possible use of topical 5-fluorouracil 5% (5-FU) in the postoperative management of challenging IPs. Methods: This is a retrospective cohort evaluation of patients with IPs attached in the frontal sinus or in the frontal recess and growing into the frontal sinus. Data on primary or revision surgery, uni- or bilaterality, attachment site, surgical procedure, 5-FU usage, recurrence and follow-up are provided. The end points are disease-free follow-up in months and recurrence. Results: Twenty cases, including fifteen revision cases, were retrieved over a period of ten years. All cases were treated endoscopically. Two cases recurred (10%) and the intervention was repeated. In eight cases, 5-FU was applied at the end of surgery. None of these cases recurred. The mean follow-up after the last intervention was 42 months (standard deviation (SD) 22.1). Conclusion: IP involving the frontal sinus is a surgical challenge that can be successfully addressed endoscopically. The topical application of 5-FU could have a place in postoperative treatment when it is difficult to be absolutely sure that all diseased mucoperichondrium or mucoperiosteum at the attachment site(s) has been completely removed.