A patient with coexistent Gaucher disease and Philadelphia positive chronic granulocytic leukemia (CGL), who subsequently developed myeloblastic leukemia, is described. The diagnosis of CGL was established according to standard clinical, morphological, biochemical, and cytogenetic data, while the diagnosis of true Gaucher disease was based on biochemical data and the presence of Gaucher cells with typical ultrastructural features in the bone marrow and spleen. Enzyme studies showed low activity of ceramide-beta-glucosidase in the patient's peripheral blood leukocytes, skin fibroblasts, and splenic tissue and the presence of increased amounts of ceramide-beta-glucoside in the spleen. This case is reported in order to draw attention to the possible coexistence of these two diseases in the same patient, as opposed to the well-recognized finding of "Gaucher-like" cells in the bone marrow of patients with CGL. Enzyme studies enable distinction between these two situations.

A rare case of simultaneous presentation of monocytic and plasma cell leukemia is reported. Cytochemistry, transmission and scanning electron microscopy confirmed the presence of a dual population consisting of monoblasts and plasma cells. Monoblasts contained nonspecific esterases, secreted lysozyme and showed dense bodies and surface ruffles under the scanning electron microscope, while the plasma cells secreted IgG kappa para-protein, contained rough endoplasmic reticulum, and showed surface blebs with microvilli. Another unusual feature of this case was the relatively chronic course of the disease, lasting 15 months after initial diagnosis.

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.