Other small B-cell lymphomas with plasmacytic differentiation (MALToma, follicular lymphoma, monomorphic B-cell lymphoma) were discounted on the absence of a background population of small neoplastic B cells and the uniform CD38+/CD138+/MUM-1+/Igκ-restricted plasma-cell phenotype (9). The gene discussed is IRF4; the disease is B-cell non-Hodgkin lymphoma.