Thank you for your interest in our study. Your comments highlight a number of issues that we feel require clarification.

Perhaps the most important question you raise is the inclusion of patients with incomplete data. We felt it was necessary to include as many patients as possible as each patient provides numerous data points that still contribute to frequency data and univariate analyses. This is common among studies that involve patients with rare pathology. It is important to note that multivariate analyses did not include patients with missing data. In order to accurately perform multivariate Cox proportions hazard regression analysis, patients with missing covariate data were automatically excluded. We apologize that this was not clearly stated in the original paper. Additionally, 5-year recurrence-free and overall-survival rates were estimated from Kaplan-Meier curves and only included patients with follow up data.

There is much debate regarding the pathologic diagnosis of many subtypes of sarcomas and it is still evolving in the current era. This is especially true for solitary fibrous tumor/hemangiopericytoma (SFT-HPC). On the basis of histological and clinical similarities and the absence of clear diagnostic criteria to distinguish subtypes, many have proposed that SFT and HPC represent different points on a broad spectrum of the same entity . Accordingly, these tumors were merged together in the fourth edition of the World Health Organization classification of tumors of soft tissue . It is routine at our institution to have these pathologic subtypes combined and it is for this reason that they are grouped in this study. We acknowledge that tumors along different points of this spectrum may lead to varying clinical behavior and we may consider this in future studies.

Again, we thank you for your interest in this study and we hope that we have addressed your concerns.