Differentiating benign notochordal cell tumors from chordomas: radiographic features on MRI, CT, and tomography
The purpose of this study was to characterize the imaging spectrum of benign notochordal cell tumors (BNCTs) and chondromas and to determine if this helped in differentiating BNCTs from chordomas. Thirty-eight patients pathologically diagnosed with chordomas were reviewed and ultimately diagnosed to have five BNCTs and 33 chordomas. The following radiologic findings were reevaluated by two radiologists by consensus: extraosseous extension, osseous change on CT or conventional tomography, T2-weighted MR signal intensity, T2-weighted signal homogeneity, and contrast-enhanced T1-weighted MR signal intensity. Fisher's exact test was performed to determine statistical significance. Our study yielded five results. First, four of five BNCTs (80%) were intraosseous, whereas 31 of 33 chordomas (94%) were both intra- and extraosseous (p < 0.0001). Second, all BNCTs showed mild osteosclerosis without bone destruction; all chordomas showed variable osteolysis (p = 0.0092). Third, all BNCTs and 28 of 33 chordomas (85%) showed hyperintensity on T2-weighted images (p > 0.05). Fourth, four of five BNCTs (80%) and 27 of 33 chordomas (82%) were heterogeneous on T2-weighted images (p > 0.05). Fifth, no BNCTs enhanced, whereas all chordomas variably enhanced (p < 0.0001). Radiologic studies may allow distinction of BNCTs from chordomas.