Surgical management of spinal solitary fibrous tumor/hemangiopericytoma: a case series of 20 patients.

PURPOSE: Spinal solitary fibrous tumor/hemangiopericytoma (SFT/HPC), a rare mesenchymal tumor that arises from pericytes of Zimmerman, comprises only 0.08% of all primary bone tumors and 0.1% of primary malignant bone tumor and rarely occurs in the spine. We attempt to correlate the clinical factors and different treatment options with the recurrence rate and overall survival of SFT/HPC over time.

METHODS: A retrospective study of 20 patients with spinal osseous SFT/HPCs who were surgically treated in our center between 2003 and 2015 was performed. Kaplan-Meier curves and log-rank tests were used to compare the survival probability or recurrence-free probability between groups, and P values < 0.05 were considered statistically significant.

RESULTS: Three surgical management strategies, including subtotal resection, piecemeal total resection, and total en bloc spondylectomy (TES) were applied. Postoperative radiotherapy was carried out in 14 cases. The mean follow-up period was 38.3 (median 35, range 7-93) months, and 6 patients passed away with the mean follow-up time of 47.7 (median 41, range 24-77) months. Relapse was detected in 9 patients (45%) with the mean time from surgery to recurrence being 36.6 (median 28, range 12-73) months. Our results indicate that grade III is an adverse prognostic factor for both recurrence and over survival (OS) for spinal osseous SFT/HPC, while total resection, especially TES, is a positive prognostic factor.

CONCLUSIONS: Spinal osseous SFT/HPC is a challenging clinical entity given its high local recurrence rate. Surgical management plays a crucial role in the whole treatment of spinal SFT/HPCs and total excision, especially TES, should be strived for whenever possible. Postoperative radiotherapy is recommended to lower the recurrent rate. This study also confirms that pathology grade III is an adverse prognostic factor for spinal osseous SFT/HPCs.