Scanning and transmission electron microscopy study on the plasma cells of a patient with multiple myeloma.

The ultrastructural features of the plasma cells of a 32-year-old patient suffering from multiple myeloma are described. The high percentage (90%) of plasma cells in the bone marrow aspirate permitted the examination of an almost homogenous population. The appearance of the plasma cells seen with the transmission electron microscope did not differ from that described in other reports. The surface architecture of the plasma cells, such as revealed by the scanning electron microscope, differed from that of the normal and pathological white blood cells. Of particular interest were the membrane-bound portions of the cytoplasm seen as 'buddings', or round bodies in the vicinity of the plasma cells which contained most probably pathological proteins.