Phenotypic characteristics of high-grade MZL and EMZ in spleens as determined by multicolor flow cytometry. Control B cells had low forward angle light scatter (FSC) and expressed IgM at normal levels, were CD5−, and approximately 65% of B cells were CD23+. High-grade MZL cells were larger than control cells, as shown by increased FSC, were IgMbrightCD5dullCD23−, and constituted 60% of total spleen cells.