Splenic MZL in F1BC NZB mice. The left column (A-D) contains low-power (5.5 × objective; bar is 5 cm) photomicrographs of selected mice spleens showing the various stages of MZL seen: early marginal zone hyperplasia and the confluence of 2 or more GCs (A-B); moderate and massive infiltration of the red pulp (C-D). The right column (E-H) shows selected areas of involvement at a higher power (43 × objective; bar is 100 μm) for cellular detail.