Cellular tumor composed of fascicles or whorly bundles of proliferating spindle cells with hyperchromatic elongated nuclei. Anaplasia is moderate and mitosis is focally active. Marker study are needed for definitive classification (SMA, SOX10, S-100, H-Caldesmon, CD117, Dog-1 and Ki-67).
Pelvic mass.
Tissue cores 1.5-1.7 cm
Pelvic mass, Tru-cut biopsy: