Myxopapillary ependymoma (spine)

There is a well-defined spinal canal solid mass at the levels of L2 and L3 that demonstrates low T1 and high T2 signal, and vivid contrast enhancement. This lesion appears intradural splaying the cauda equine nerve roots laterally. No signs of internal calcifications or hemorrhage. There is no expansion of the spinal canal or signs of scalloping over the posterior columns of the vertebral bodies. The intervertebral foramina are capacious and not involved. The remainder of the lumbar spine appears unremarkable. 

There is a significant distortion of the thecal sac in the mid thoracic column, at T6 to T8 levels. The cord is markedly distorted in the region and pushed back posteriorly. The cord appears to be tagged posteriorly at several points, and the source of this is not appreciated, appearances are those of posterior adhesions with the dorsal aspect of the sac. Altered CSF flow mechanics within the region contributes to dephasing loss of signal within the CSF. The vertebral bodies, intervertebral discs, and intervertebral foramina are unremarkable. 

CLINICAL NOTES: Slip 1 Lumbar intradural lesion. Slip 2 Thoracic cyst wall. Slip 3 Lumbar intradural lesion and thoracic arachnoid adhesions - thick wall, arachnoid.

MACROSCOPIC DESCRIPTION:

1. "Thoracic spinal cyst" FS/SMEAR DIAGNOSIS: Fibrous tissue. Benign.
2. "Lumbar intradural lesion" FS DIAGNOSIS: Myxopapillary ependymoma.
3. "Lumbar intradural lesion"
4. "Thick wall"
5. "Arachnoid"

MICROSCOPIC DESCRIPTION: 1,5. Sections show unremarkable dense fibrous connective tissue, consistent with a ligament. No tumor is seen. 2,3. Sections show a moderately cellular myxopapillary ependymoma composed of well-formed perivascular pseudorosettes with central hyalinized blood vessels and micro cystic structures containing myxoid material. Radially arranged bland tumor cells contain oval nuclei with fine chromatin and inconspicuous nucleoli. No mitoses, necrosis or microvascular proliferation are seen. 4. Sections show unremarkable arachnoidal tissue composed of loose collagen fibers partially lined by meningothelial cells. No tumor is seen. 

DIAGNOSIS:

1. Thoracic spine, cyst: Unremarkable dense fibrous tissue.
2. Lumbar spine, intradural lesion: Myxopapillary ependymoma (WHO I).
3. Lumbar spine, intradural lesion: Myxopapillary ependymoma (WHO I).
4. Thick wall: Unremarkable arachnoidal tissue.
5. Arachnoid tissue: Unremarkable dense fibrous tissue.

Slides courtesy of Prof. Michael Gonzales - RMH Pathology Department