摘要Background:Sinonasal inverted papilloma (IP) is a rare benign tumor of the nasal cavities and paranasal sinuses.It is destructive or bone-remodeling,tends to recur after surgical resection,and has a significant malignant potential.The present study aimed to perform a retrospective analysis of patients with squamous cell carcinoma (SCC) arising from IP,including characteristics,survival outcome,and predictors of associated malignancy.Methods:The medical records of 213 patients diagnosed with IP from January 1970 to January 2014 were retrospectively reviewed.Eighty-seven patients were diagnosed with SCC/IP; their clinical characteristics,treatments,and survival outcomes were analyzed.Results:Of the 87 patients with SCC/IP,the 5-and 10-year overall survival outcomes were 39.6％ and 31.8％,respectively.Twenty-nine of these patients received surgery and 58 received combined surgery and radiation.Of the patients with stages Ⅲ-Ⅳ,the 5-year survival rate was 30.7％ for those treated with surgery only and 39.9％ for those given the combination treatment (P =0.849).Factors associated with significantly poor prognosis were advanced-stage,metachronous tumors,or with cranial base and orbit invasion.Age,synchronous or metachronous tumors,and pathological stage were independent risk factors for mortality,shown by multivariate analysis.Conclusion:Patients with SCC/IP had low overall survival outcomes.Advanced age,stage,and metachronous tumors are the main factors affecting prognosis.Treatment planning should consider high-risk factors to improve survival outcome.