The upper lymph node shows involvement by follicular lymphoma, while the lower node shows a diffuse pattern, due to diffuse growth of large lymphoid cells.
From Warnke, RA, Weiss, LM, Chan, JK, Cleary, ML, Dorfman, RF. Tumors of the lymph nodes and spleen. Atlas of tumor pathology (electronic fascicle), Third series, fascicle 14, 1995, Washington, DC. Armed Forces Institute of Pathology.