Plasma cell leukemia and myeloma: a scanning electron-microscopic study of cell surface features in six cases.

Circulating plasma cells from six patients who had plasma cell leukemia were examined by transmission and scanning electron microscopy. In all cases, leukemic plasma cells constituted more than 60% of the total cell population in the peripheral blood. Transmission electron microscopy confirmed that the leukemic cells were plasmacytic and that many of them contained parallel arrays of rough endoplasmic reticulum and a prominent Golgi apparatus. Scanning electron microscopy confirmed previous observations of cultured myeloma cells and showed that plasma cells display varying numbers of surface blebs in addition to short stublike microvilli. The microvilli were frequently clustered together in one area of the surface. Bleb formation appears to be characteristic of plasma cells, but its nature is still obscure. Current knowledge of this phenomenon is briefly reviewed.