PMC8769484_01
Lumbar spine CT showed high absorption at the L3 vertebral level (A), and lumbar MRI T1-weighted images showed faint high signal (B) with low signal on T2-weighted images with a clear hard border (C, E, F), suggesting an intramembranous extramedullary tumor occupying the spinal canal and excluding the cauda equina ventrally (E, F). Contrast-enhanced MRI showed a uniform contrast effect within the tumor (D). There was no dural tail sign, and continuity between the dura mater and the tumor could not be determined from the images.
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F1
T1-weighted images showed faint high-signal (Fig. 1B) with low-signal on T2-weighted images with a clear hard border (Fig. 1C, 1E, and 1F), suggesting an intramembranous extramedullary tumor occupying the spinal canal and excluding the cauda equina ventrally (Fig. 1E and 1F). Contrast-enhanced MRI showed a uniform contrast effect within the tumor (Fig. 1D). There was no dural tail sign, and continuity between the dura mater and the tumor could not be determined from the images. Pathological analysis revealed substantial tumor cells with pale cytoplasm, classified as corded collagen fiber bundles (Supplementary Fig. 1A and 1B; Supplementary materials are available online). Tumor cells were positive for PAS (Peridodic acid schiff) (Supplementary Fig. 1C) and negative for digestive PAS (Supplementary Fig. 1D), and immunostaining was positive for EMA (Supplementary Fig. 1E) and negative for GFAP (Glial fibrillary acidic protein). The MIB-1 index was less than 1% (Supplementary Fig. 1F).
After L3 laminectomy, median dural incision was performed, and the tumor was found to be in close contact with the left lateral side of the dura mater (arrow), with some areas encased by the arachnoid and others compressing and excluding the arachnoid (A, D). On the ventral side of the tumor, there was adhesion to one cauda equina, but through the arachnoid membrane and could therefore be bluntly dissected off (B, E). The tumor was slightly yellowish in color and hard, and was totally removed piece by piece (C). (*: tumor, : nerve root).
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F2
After L3 laminectomy, median dural incision was performed, and the tumor was found to be in close contact with the left lateral side of the dura mater, with some areas encased by the arachnoid and others compressing and excluding the arachnoid (Fig. 2A and 2D). On the ventral side of the tumor, there was adhesion to one cauda equina, but through the arachnoid membrane and could therefore be bluntly dissected off (Fig. 2B and 2E). The tumor was slightly yellowish in color and hard, and was totally removed piece by piece (Fig. 2C).