electron microscopic study of the canine transmissible venereal sarcoma ( n = 26 ) at different stages of growth showed that tumors in a progressive phase of growth ( n = 12 ) were comprised mostly of large , round cells with prominent nuclei and nucleoli , a few spindle-shaped cells and collagen fibers , focal areas of necrosis , and lymphocyte infiltrates .
C0007610
nuclei
C0007609
nucleoli