Clinical features of nasal and sinonasal inverted papilloma associated with malignancy

Objective: Nasal and sinonasal inverted papilloma (IP) are rare benign tumors and have the potential to exhibit malignancy in approximately 10% of cases. This study aimed to analyze the clinical features of IP associated with malignancy. Furthermore, we reviewed our therapeutic strategy and the clinical course of malignant IP. Methods: Overall, 70 patients with IP at our institution were retrospectively analyzed from April 2006 to December 2015; of these, six (9%) had associated malignancy. Data was collected on sex, age, presenting symptoms (nasal bleeding, rhinorrhea, facial or cheek pain, and nasal obstruction), bone destruction, and extent of disease on CT and MRI. Categorical data of patients with and without malignancy were compared using the chi-square test. A p value of <0.05 was considered statistically significant. Our therapeutic strategy for IP with malignancy, particularly the surgical procedure, i.e., the external incision or the endoscopic nasal approach, varied based on when the carcinoma was detected. In addition, we considered postoperative radiation therapy depending on histological examination. Results: Nasal bleeding (p < 0.001), pain (p = 0.040), bone destruction (p < 0.001), and extent of disease (p = 0.026) on CT and MRI findings were significantly associated with malignancy. Carcinoma was diagnosed preoperatively in two (33%) and postoperatively in four patients (67%). We operated five patients (one case was not treated because of end-stage pancreatic cancer). Two patients underwent endoscopic sinus surgery (ESS) alone, two ESS plus Denker's method, and one ESS plus anterior craniotomy. Three patients underwent surgery only, and two patients received postoperative radiotherapy. The median follow-up period was 69.3 months. One patient died of the disease and the remaining patients are alive without recurrence. Conclusion: For IP patients exhibiting these clinical findings preoperatively, we should suspect complication with malignancy and plan a treatment. Even if postoperative histology does not confirm malignancy, we should ensure careful observation because of metachronous malignant transformation or the possibility to overlook small malignant lesions. Our result suggests that our strategy for malignant IP could be a reasonable option. (C) 2018 Elsevier B.V. All rights reserved.