A. Brief Descriptions：
B. Gross Findings：
Well-circumscribed (infiltrate microscopically), larger, softer with necrosis, hemorrhage, and cystic degeneration.
C. Micro Findings：
Malignant spindle cells: elongated, blunt-ended nuclei and acidophilic, fibrillary cytoplasm.
Growth in interlacing cords, with palisading of nuclei.
Nuclear atypia, large bizarre nuclei or pyknotosis.
High mitotic activity (>20/50 HPF).
Some round cells with clear space surrounding nucleus.
What is GIST (gastrointestinal stromal tumor) ?
What is epitheliod leiomyosarcoma ?
Robbins Pathologic Basis of Disease, 6th ed. P1266.
【 Fig. 151-1 (LP)】 Interlacing of spindle cells without any special arrangement.
【 Fig. 151-2 (LP)】 Spindle cells with elongated blunt-end nuclei.
【 Fig. 151-3 (LP)】 Spindle cells with elongated, blunt-end nuclei; note high mitotic activity.