Figure 1.

On conventional HE staining a lymph node with vanished lymph node structure and focal necrosis and perinodal lymphatic infiltrates were seen (a). At higher magnification (b, c), a blastic infiltrate with strong apoptotic activity and many macrophages engulfing apoptotic nuclear bodes were visible. Immunolabeling confirmed the B-cellular lineage of most blastic cells (d: CD20) with macrophages cells lying in between (e+f: CD68). Part of the blastic cells was positive for EBNA2 (g) and EBV late membrane antigen (h: LMP). Overall, there was a high proliferative activity (i: Mib-1 positivity in about 80-90% of B-blasts). Additionally, a lot of CD3 (j)/CD8 (k) positive T-cells were interspersed, with hardly any CD4-positive T-helper cells identifiable (l). The T-cells were positive for perforin (m) and granzyme B (n). (a-c: hematoxylin eosin stainings; d-n: immunostainings with the antibodies indicated above) (magnification bars: a: 500 μm; b: 100 μm; c: 22 μm; d, e, g, i-n: 50 μm; f, h, l: 40 μm).