Endoscopic resection of sinonasal ossifying fibroma: 31 cases report at an institution.A retrospective analysis of 31 lesions undergoing endoscopic surgery between 2006 and 2012 was undertaken. 
Endoscopic resection
The data of patients' demographics, clinical features, operative parameters, follow-up period, and treatment outcomes were collected. 
The data of patients' demographics
The data of patients' demographics, clinical features, operative parameters, follow-up period, and treatment outcomes were collected. 
operative parameters
The data of patients' demographics, clinical features, operative parameters, follow-up period, and treatment outcomes were collected.  During the follow-up period (median: 25 months, range 4-80 months), 4 cases developed recurrences and there was no evidence of recurrence in the additional 27 cases included 8 cases living with no progressively growing residual tumor and 19 cases living without diseases. 
follow-up period
The data of patients' demographics, clinical features, operative parameters, follow-up period, and treatment outcomes were collected. 
treatment outcomes