In SMZL, the tumor is centered around the white pulp which shows replacement of preexisting lymphoid follicles by micronodular tumoral infiltrates. At low magnification, one sees a marginal zone differentiation with a biphasic appearance (not readily apparent in this particular image). The center of the follicles show darker small lymphocytes with scant cytoplasm and round or oval nuclei. They merge with larger pale-staining cells in the marginal zone that have more abundant cytoplasm and irregular nuclei. Some tumor nodules may show a residual reactive germinal center.