Representative tissue microarray cores of patients with follicular lymphoma. The image on the left shows the uncommon finding of large numbers of macrophages both within and surrounding neoplastic follicles (n = 12). The image on the right shows the more common finding of very few macrophages (n = 87). The insert shows the typical strong cytoplasmic staining of reactive macrophages with anti-CD68 antibody. Images were acquired using a Nikon Eclipse E600 clinical microscope and Dxm1200 digital camera and software (Nikon, Tokyo, Japan). Original magnification × 100 (objective, 10 ×/0.3 NA) for the larger panels and × 1000 (objective, 100 ×/1.3 NA) for the insert.