PMC4901015_01
38-year-old male with intradural extramedullary lumbar spinal Ewing tumor. Sagittal, noncontrast, T1-weighted image shows a large intradural tumor filling the spinal canal. It has a hypointense solid component (yellow arrow) and two cystic components. These are mildly and intensely hyperintense, the latter due to the proteinaceous nature of the cystic fluid (blue and red arrows, respectively).
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T1-weighted images (Fig. 1, yellow arrow), isointensity on T2WI (Fig. 2, yellow arrow), and modest enhancement (Fig. 3, yellow arrow). This solid component measured 6.5 cm in the vertical dimension and entirely filled the spinal canal.
38-year-old male with intradural extramedullary lumbar spinal Ewing tumor. Sagittal, contrast-enhanced, T1-weighted image with fat saturation (0.1mmol / kg of Magnevist) shows modest enhancement of the solid component (yellow arrow). The cystic component (green arrow) shows enhancing septa. The blue and red arrows indicate the cystic component; the T1 hyperintensity of the inferior component is possibly due to old blood products.
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T1-weighted images (Fig. 1, yellow arrow), isointensity on T2WI (Fig. 2, yellow arrow), and modest enhancement (Fig. 3, yellow arrow). This solid component measured 6.5 cm in the vertical dimension and entirely filled the spinal canal. T2 (Fig. 2, blue and red arrows). These cystic components did not show significant enhancement, although enhancing septations (Fig. 3, green arrow) and mural nodules (Fig. 4, red arrow) were present. The high T1-weighted signal in the cystic component suggested high protein content and/or hemorrhage.
38-year-old male with intradural extramedullary lumbar spinal Ewing tumor. Tumor consisted of undifferentiated small round cells arranged in patternless sheets. Haematoxylin and eosin. X400.
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Histopathology demonstrated a malignant small round-cell tumor arranged in patternless sheets (Fig. 5), strong immunopositivity for CD99 with a membranous pattern (Fig. 6), and scattered cytoplasmic immunoreactivity for S-100 protein though negative for keratin-suggesting a Ewing sarcoma.
38-year-old male with intradural extramedullary lumbar spinal Ewing tumor. Fluorescence in-situ hybridization (FISH) with an EWSR1 breakapart probe set showed numerous nuclei with separate red and green signals (white arrows), indicating rearrangement of the EWS locus, characteristic of Ewing sarcoma. FISH with Vysis EWSR1 probe set. X1000.
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Fluorescence in-situ hybridization using a break-apart Ewing's Sarcoma Region 1 (EWSR1) probe set showed a split signal in about 50% of the interphases, indicating a translocation involving the Ewing sarcoma (EWS) locus (Fig. 7, arrows).