Differentiation of spinal schwannomas and myxopapillary ependymomas: MR imaging and pathologic features.

STUDY DESIGN

Retrospective clinical study.

OBJECTIVE

The objective of this study is to evaluate magnetic resonance imaging and pathologic features of spinal schwannomas (SCHs) and myxopapillary ependymomas (MPEs) with focus on differentiating 2 disease entities.

SUMMARY OF BACKGROUND DATA

Few studies have reported on the differentiation of SCHs and MPEs.

METHODS

Fifty-three patients were retrospectively reviewed with histologically confirmed spinal SCHs (41 patients) or MPEs (12 patients) of the cauda equina and/or conus medullaris. We evaluated neurological deterioration after surgery in association with the intraoperative findings of the tumor, as well as with the preoperative magnetic resonance images and postoperative histologic findings.

RESULTS

Patients in the SCH group had a greater mean age at surgery and a greater mean disease duration. In the SCH group, all 24 tumors that were homogeneously hyperintense on the T2-weighted (T2W) images showed rim enhancement on the postcontrast T1-weighted (T1W) images. Moreover, all 14 of the SCHs with homogeneous enhancement on the postcontrast T1W images were isointense on the T2W images. However, in the MPE group, all 8 of the tumors that were homogeneously hyperintense on T2W images showed homogeneous enhancement on their postcontrast T1W images.

CONCLUSIONS

It is very important to differentiate SCHs and MPEs before surgery, because there are reported cases of dissemination of MPEs through cerebrospinal fluid throughout the neuraxis; the tumor must be removed en block to prevent this. Although MPEs and SCHs may have similar imaging characteristics, detailed examination of the magnetic resonance T2W image and postcontrast T1W image facilitates their differentiation.