Microscopic Findings:

The tumor was composed of a cellular proliferation of elongated spindle cells in a fascicular growth pattern with moderate cytologic atypia and occasional mitotic figures (~3/10 hpf).

See Figures 4-6.

Figure 4. H&E, 10x.	Figure 5. H&E, 20x.	Figure 6. H&E, 40x.

Additionally, the tumor was seen to infiltrate upward into the small bowel mucosa with associated ulceration.

See Figures 7-8.

Figure 7. H&E, 20x	Figure 8. H&E, 40x

Immunohistochemical stains were performed with appropriate control staining.

CD117 (C-Kit) was diffusely and strongly positive within the tumor and negative in surrounding smooth muscle. Smooth muscle actin (SMA) faintly stained the tumor but strongly stained the muscularis propria.

See Figures 11-12.

Figure 11. CD117, 20x. Tumor with adjacent muscularis propria.	Figure 12. Smooth muscle actin, 20x. Tumor with adjacent muscularis propria.