CD23 strongly stains the cytoplasm and membranes of follicular dendritic cells and the membranes of a subset of follicular mantle zone B-lymphocytes. Typically, B-cell small lymphocytic lymphoma/chronic lymphocytic leukemias are CD5 positive and CD23 positive, which aids in the differentiation from other B-cell lymphomas that may be CD5 positive but CD23 negative.