Presurgical role of MRI tractography in a case of extensive cervicothoracic spinal ependymoma

Abstract

Background: Intramedullary spinal ependymoma is a tumor, hardly characterizable with conventional magnetic resonance (MR) imaging only. MR diffusion tensor imaging (DTI) with three-dimensional fiber-tracking reconstructions allows the evaluation of the relationship between neoplasm and white matter fiber tracts, being a powerful tool in presurgical planning. We present DTI findings in a case of a young female with an extensive cervicothoracic spinal ependymoma.

Case description: The patient complained of a 2-month history of acute urinary retention, weakness and numbness on the lower limbs and the upper left limb. She underwent MR imaging that showed an extensive cervicothoracic spinal mass, difficult to characterize with conventional MR sequences. DTI showed peripherally displacement of fibers, without involvement of the spinal cord, findings consistent with an ependymoma. The patient underwent surgery with a complete resection "en bloc" of the lesion, which showed clear cleavage planes, as detected by DTI. Histopathological findings confirmed the diagnosis of ependymoma.

Conclusions: DTI is a useful tool in presurgical planning, helping in differentiating not infiltrating neoplasms, such as spinal ependymomas, from other infiltrative and more aggressive neoplasms, which are considered not resectable.

Keywords: Cervicothoracic tract; DTI; ependymoma; spinal cord.

Figure 1

Spinal cord MRI of a young patient affected by an extensive cervicothoracic spinal ependymoma. (a) Consecutive sagittal T2-weighted images show a cervicothoracic spinal ependymoma with a solid part (arrows), some cystic parts (arrowheads) and a small amount of late sub-acute bleeding inside the neoplasm (methemoglobin) (empty arrow). Note the syringomyelia at T6-T9 level (a’ – empty arrowhead). Note also caliber change of the spinal cord at C2-C3 level and moderate widening of spinal canal. (b) Sagittal noncontrast T1-weighted shows a cervicothoracic spinal ependymoma with a solid part (arrow), some cystic parts (arrowhead), and a small amount of late sub-acute bleeding inside the neoplasm (methemoglobin) (empty arrow). (c) Sagittal post-contrast T1-weighted image shows the cervicothoracic extension of ependymoma's solid part. (d) Sagittal DWIBS-MIP reconstruction, (e) sagittal ADC map and (f) fused T1-weighted/DWIBS images show a high restriction of diffusion a the level of ependymoma's solid part, respectively high, low and high (red) signal intensity. (g) Sagittal T2-weighted images show, at C6-C7 and (g’) C5 level, white matter peripheral displacement surrounding ependymoma (empty arrows) and a small intralesional cyst (arrowhead), respectively

Figure 2

Spinal cord MRI tractography of a young patient affected by spinal ependymoma. The panel shows no infiltration of the spinal cord but rather cord fibers peripherally displacement. (a and b) Sagittal post-contrast T1-weighted images, without (a) and with (b) spinal cord tractography overlayed, show the extension of ependymoma's compact part. Note the change in caliber of spinal cord at C2-C3 level. (c-e) Sagittal color-coded fractional anisotropy (FA) map (c), FA map, (d), and ADC map (e), show low intensity values (arrows) corresponding to the ependymoma, centrally placed. (f-i) Sagittal color-coded FA map with spinal cord tractography overlaid shows different point of fiber displacement (arrows), rather than infiltration, by ependymoma. Images h, i, and l were obtained by using a “virtual cut” of part of the spinal cord fibers obtained respectively at C3-C4 (h) and C2-C3. (i,j) levels. (l) Axial color-coded FA map with spinal cord tractography overlaid and (k) T2-weighted images at C2-C3 level shows white matter peripheral displacement surrounding ependymoma. Arrow indicates fibers lack in the central part of spinal cord, caused by a central position of the neoplasm

Figure 3

Histological appearance of spinal ependymoma. Histological examination reveals a tumor composed of glial cells with oval nuclei and fibrillary processes arranged in perivascular pseudorossettes (Hematoxylin and eosin stain; original magnification, ×100)