Fig. 11. Small lymphocytic lymphoma/B-cell chronic Lymphocytic leukemia. A. A diffuse infiltrate with a vague nodular pattern from the presence of “proliferative centers” (hematoxylin and eosin, × 2). B. A monomorphous infiltrate of small lymphocytes (hematoxylin and eosin, × 10). C. The cytologic features of neoplastic lymphocytes: the cells are small with small dark nuclei and inconspicuous cytoplasm (hematoxylin and eosin, × 60). D. CD5 stain is positive in this subclass of lymphoma (hematoxylin and eosin, × 40). (Courtesy of Dr. A. Mowat.)