a type of low-grade non-Hodgkin lymphoma characterized by enlarged lymph nodes and other lymphoid tissue or bone marrow that are infiltrated by small lymphocytes. May be associated with features of chronic lymphocytic leukemia such as lymphocytosis, lymphadenopathy, and, in late stages, hepatosplenomegaly, anemia, and thrombocytopenia. Histology is identical between these two disease entities; it consists of predominantly small lymphocytes with condensed chromatin and round nuclei. Larger lymphocytes (prolymphocytes and paraimmunoblasts) with more prominent nucleoli and dispersed chromatin are always present, usually in clusters. Characteristic immunophenotype of these cells is CD5 and CD23 positivity, in addition to B-cell associated antigens CD19 and CD20. CD23 positivity is useful to distinguish this disease from mantle cell lymphoma, which does not express the antigen. SYN: well-differentiated lymphocytic lymphoma, white spot disease (1).