Dividing fibrosarcoma cells. Coloured scanning electron micrograph of fibrosarcoma (fibroblastic sarcoma) cells in the late telophase stage of mitosis. The cells are covered in many filopodia. Fibrosarcoma is a malignant tumour derived from fibrous connective tissue of the bone and characterized by immature proliferating fibroblasts or undifferentiated anaplastic spindle cells. Magnification: x4000 when printed at 10 centimetres wide.