Differentiation of spinal giant cell tumors from chordomas by using a scoring system

Introduction: Few reports have compared the clinical features and imaging characteristics of giant cell tumor and chordoma of the spine. The aim of the present study was to investigate whether the two types of tumors could be differentially diagnosed, by comparing clinical characteristics as well as magnetic resonance imaging (MRI) or computed tomography (CT) findings and then scoring the characteristic findings. Methods: A total of 18 patients were retrospectively assessed. To elucidate the characteristic findings, we investigated the following 10 items: age at diagnosis, sex, and site of occurrence; for MRI findings, the pattern of tumor expansion, T1-weighted images, T2-weighted images, septal structure, and cystic changes; and for CT findings, calcification or residual bone fragments and incomplete bone shells. Then, we developed a unique scoring system and investigated whether the two tumors could be differentiated by this scoring system. Results: Six items, including, age, site of occurrence, tumor expansion pattern, T2-weighted images, septal structure, and incomplete bone shells, were significantly different between giant cell tumor and chordoma patients. By using newly developed scoring system, the mean scores of 0.9 ± 0.6 (range 0–2) for giant cell tumor and 4.8 ± 1.5 (range 3–6) for chordoma patients were significantly different (P < 0.001), thereby allowing the differential diagnosis by setting the cutoff value to three. Conclusions: We found that the six items were useful for differentially diagnosing giant cell tumor and chordoma. These results indicate that it may be possible to distinguish the two types of tumor by scoring these items.