Transmission and scanning electron microscopy findings in 37 patients with monocytic leukemia.

The ultrastructural features of the monocytic blast cells of 37 patients with M4 and M5 types of leukemia were examined with transmission (TEM) and scanning (SEM) electron microscopes. The cells showed a large variety in nuclear size and shape, dependent on the stage of cell differentiation. Nuclear pockets, appendices and bridges were observed. The cytoplasm contained perinuclearly located fibrils, occasionally elongated mitochondria and Auer bodies. The surface ultrastructure of the cells was similar to that of healthy monocytes, but often numerous blebs were observed.