[Risk factors of malignant transformation of sinonasal inverted papilloma]

Objective:To explore the risk factors of malignant transformation of sinonasal inverted papilloma （SNIP）, and to improve the accuracy of preoperative diagnosis of tumor. Methods:The clinical data of 89 patients with sinonasal inverted papilloma （SNIP group, n=60） and malignant transformation of sinonasal inverted papilloma （IP-SCC, n=29） were analyzed retrospectively. Clinical symptoms, medical history, endoscopic examination, characteristic of sinonasal CT scan and MR imaging were collected and compared between two groups. Then the indicators with significant differences between the two groups were used for binary logistic regression analysis. The logistic regression model was established to predict the malignant transformation risk factors of inverted papilloma and the prediction ability of the regression model was estimated. Results:The significant differences between the two groups were: symptoms, including nasal obstruction, purulent mucus, blood in the nasal discharge; long-term smoking history; tumor attached with purulent mucus; CT scan showing bone destruction of the orbital wall and skull base; MR Imaging showing convoluted cerebriform pattern （CCP） sign, intraorbital involvement, and dural enhancement of the skull base. The results of logistic regression analysis showed that the risk factors of malignant transformation of SNIP were blood in the nasal discharge, long-term smoking history, tumor with purulent discharge, orbital wall destruction on CT scan, disappearance of CCP and orbital involvement on MRI. The accuracy rate of regression model for predicting malignant transformation of IP is 75.0%, and the accuracy rate for benign inverted papilloma is 96.7%, and the overall accuracy of the model is 89.8%. Conclusion:The risk factors for predicting malignant transformation of SNIP are blood in the nasal discharge, long-term smoking history, tumor with purulent discharge, orbital wall destruction on CT scan, and disappearance of CCP sign and orbital involvement on MRI. It's necessary to analyze all of clinical factors in order to improve the accuracy of preoperative diagnosis of sinonasal inverted papilloma.