PMC4666522_01
(A) Sagittal T1-weighted image demonstrated isointensity intradural mass at T12-L1. (B) Sagittal T2-weighted image demonstrated iso or slightly high-intensity intradural extramedullary mass at T12-L1 near the conus medullaris. (C) Coronal post-gadolinium T1-weighted image showing that the congestive pial vein extended to the level of T11 (white arrow). (D) Sagittal post-gadolinium T1-weighted image demonstrated a 28 x 14 mm enhanced intradural extramedullary mass at T12-L1 near the conus medullaris. (E) Axial post-gadolinium T1-weighted image demonstrated that the tumor had compressed the conus medullaris to the left ventral side.
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However, thoracic-lumbar spinal magnetic resonance imaging demonstrated a homogeneously enhancing focal intradural extramedullary lesion at T12-L1 near the conus medullaris (Fig. 1A-E).
After opening the dura mater, adhesion between the arachnoid membrane and dura mater was confirmed in the dorsal aspect of the tumor (black arrow).
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After dura mater was exposed and incised, the local arachnoid membrane displayed adhesion and thickening to the dura in the dorsal aspect of the tumor (Fig. 2).
Macroscopic appearance of the tumor at surgery: the tumor had involved a lumbar nerve root and attached to the filum terminale. The double black arrows indicate the lumbar nerve root that had been encompassed by the tumor.
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The tumor was carefully lifted, but was not freed because of its large size and adhesion to the filum terminale and lumbar nerve root (Fig. 3).
The tumor had not adhered to the conus medullaris (white arrow). Additionally, the tumor had attached to the filum terminale, which was determined to be remarkably narrowed (black arrow).
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Additionally, the region where the tumor had attached to the filum terminale was abnormally thin (Fig. 4).
(A) Perivascular pseudorosettes were identified (black arrow). There were no features unique to the myxopapillary subtype, such as mucin (hematoxylin and eosin, original magnification x 100). (B) Image showing tumor cells immunoreactive for GFAP is focal (original magnification x 100). (C) Ki-67 immunostaining of the tumor showing a mitotic index of 1-3% (original magnification x 200).
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It confirmed non-myxopapillary ependymoma (WHO grade 2) with a Ki-67 index of 1-3% (Fig. 5A-C).