Histopathology. (a) Hematoxylin and eosin stain demonstrates a densely cellular spindle cell malignancy in partly fascicular or storiform pattern and areas of necrosis (100x magnification). (b) A higher magnification (200x) hematoxylin and eosin stain shows pleomorphic cells with a high mitotic rate, exceeding 20 mitoses per 10 high power fields. (c) The Ki-67 index is estimated at >75% (100x magnification). (d) Immunohistochemical staining for p53 nuclear expression is seen in >90% of cells (100x magnification).