CLINICAL CASE SERIES SPINE Volume 37, Number 1, pp E37–E45 ©2012, Lippincott Williams & Wilkins Spine www.spinejournal.com E37 Giant Cell Tumor of the Mobile Spine A Review of 49 Cases Stefano Boriani, MD,* Stefano Bandiera, MD ,* Roberto Casadei, MD,† Luca Boriani, MD ,† Rakesh Donthineni, MD, MBA,‡ Alessandro Gasbarrini, MD,* Elettra Pignotti, MSc,§ Roberto Biagini, MD,¶ and Joseph H. Schwab, MD, MS  Study Design. This is a retrospective review of 49 cases of giant cell tumor (GCT) of the mobile spine treated surgically. Objective. Our goal was to determine which factors influenced local recurrence. Summary of Background Data. GCT is a benign, locally aggressive tumor that rarely occurs in the spine. The management of local recurrence can be challenging. Methods. We performed a retrospective analysis of GCTs of the mobile spine managed between 1970 and 2005. Median follow-up was 145 months with a minimum of 2 years or until death. We used the Kaplan-Meier method to test whether Enneking stage, surgery type, and surgical margin had statistically significant impact on local recurrence. The log rank test was used for comparison, and a P value of less than 0.05 was deemed significant. Results. Of the 49 patients, 11 (22%) local recurrences occurred. The latest recurrence occurred at 60 months. Age less than 25 years was associated with a worse relapse-free survival ( P = 0.03). En bloc resection was associated with better local control with Enneking stage III tumors ( P = 0.01); however, intralesional resection provided adequate control of Enneking stage II tumors. There were 6 (12%) cases of metastasis, and 2 patients died from the progression of their disease. One patient died from the complications of the surgery. Conclusion. En bloc resection should be considered for Enneking stage III GCTs of the mobile spine. The choice of en bloc resection must be balanced with the inherent risks of the procedure. Intralesional resection of Enneking stage II tumors provides adequate G iant cell tumor (GCT) is a well-known primary bone tumor. The incidence in the mobile spine (above the sacrum) ranges from 1.4% to 9.4%. 1–5 GCTs usu- ally occur in the vertebral body as opposed to the posterior elements. They commonly have a lytic appearance on radio- graphs. The presentation of these tumors is usually solitary, although multicentric presentations have been documented. 6 ,7 Although there are many published reports on various aspects of extremity GCT, there are only a few focusing on GCT of the mobile spine, and even these have limited numbers of cases. GCTs of the mobile spine have been reported to afflict slightly younger patients than what has been reported in the extremity. 3 While these properties can be suggestive of GCT, the diagnosis must be confirmed by histological analysis. 2 ,8 The classic appearance of GCT on histology is that of mul- tinucleated giant cells distributed in a background of mono- nuclear and spindle-shaped cells. The tissue is highly vascular and usually without stroma. 9 Although it is a benign tumor, it can be locally aggressive. GCTs are known to metastasize with variable outcomes. 10 ,11 Early thoughts about GCTs being malignant due to their locally aggressive behavior and meta- static potential have been reconsidered. 12 Even though it can be very aggressive locally and metastasize, GCT is still con- sidered a benign entity, and the surgical approach must bear that in mind. Previously published reports on GCTs occurring in the spine have had small numbers or were written prior to the era of en bloc resection. 2–4,9,13,14 Fidler reported 9 cases of GCT successfully treated with en bloc resection. 15 The largest con- temporary report was a series of 22 cases in the cervical spine. The authors reported an overall local recurrence rate of 28%. They also reported that local control rates were improved with en bloc resection. 16 The goal of our study was to describe a large series of GCT in the mobile spine. We were specifically interested in identi- fying the rate of local recurrence and to elucidating factors associated with local recurrence. From the *Department of Spine Oncology, Rizzoli Institute, Bologna, Italy; †Department of Oncologic Surgery, Rizzoli Institute, Bologna, Italy; ‡Alta Bates Medical Center, Berkeley, CA; §Statistical Analysis TF, Rizzoli Institute, Bologna, Italy; ¶Department of Orthopedic Oncology, IFO, Rome, Italy; and Department of Orthopedic Surgery, Massachusetts General Hospital, Boston, MA. Acknowledgment date: October 11, 2010. Revision date: February 18, 2011. Acceptance date: April 4, 2011. The manuscript submitted does not contain information about medical device(s)/drug(s). No funds were received in support of this work. No benefits in any form have been or will be received from a commercial party related directly or indirectly to the subject of this manuscript. Address correspondence and reprint requests to Joseph H. Schwab, MD, MS, Sections of Orthopedic Oncology and Spine Surgery, Department of Orthopedic Surgery, Massachusetts General Hospital, 55 Fruit Street, Boston, MA 02114; E-mail: jhschwab@partners.org local control. Patients should be followed for at least 5 years because local relapse can occur late. Key words: giant cell tumor of bone, mobile spine, local recurrence. Spine 2012;37:E37–E45 DOI: 10.1097/BRS.0b013e3182233ccd Copyright © 2012 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.