Adult Primary Spinal Epidural Extraosseous Ewing’s Sarcoma: A Case Report and Review of the Literature

Figure 2

Histologic findings. (a) H&E stain within the tumor shows the small round blue cell appearance. (b) Ki67 immunostaining indicates a very high mitotic index (60–70%). (c) H&E stain demonstrates tumor invasion through the perineurium and into the right T11 nerve root. (d) Tumor invasion in the T11 nerve root is demonstrated by tumor cells interspersed within S100-positive Schwann cells. The tumor itself was S100-negative. H&E: hematoxylin & eosin.

(a)

(b)

(c)

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