Figure 1

H&E × 300 except as noted. A, SLL, showing mainly round nuclei containing one to several nucleoli; a rare mitotic figure is shown at upper center. B, FL, containing both centroblasts (arrows) and centrocytes with smaller darker nuclei (arrowheads). C, Low-grade MZL. Typical MZL cells form an expanded marginal zone and have round to ovoid nuclei separated by plentiful lightly staining cytoplasm. D, High-grade MZL++ composed of a heterogeneous population dominated by large cells and featuring numerous mitotic figures (E) MZL as detected in spleen biopsy (left) and necropsy (right) samples, showing progression from low grade to high grade, respectively, with retention of the same clonal J_H rearrangements (center panel). The interval from biopsy to necropsy was 40 days, with spleen weight increasing from approximately 300 to 600 mg (× 50). F, DLCL(CB) composed of large cells with round, vesicular nuclei containing two distinct nucleoli adhered to the nuclear membrane. (G) DLCL(IB), containing a high proportion of typical immunoblasts (arrows). H, LL, composed of fairly uniform, closely packed cells with ovoid nuclei, containing one to several nucleoli, interspersed with macrophages (arrow) containing apoptotic bodies.