Light micrograph of small cell lymphoma involving the kidney. Small cell lymphoma is a malignancy of lymphocytes. It can spread throughout the body and involve multiple organs, such as the kidney in this image. The lymphoma cells (numerous small blue dots) infiltrate in between kidney tubules (round structures with white centres). A glomerulus (larger round structure in upper left corner) is also seen. Haematoxylin and eosin stained tissue section. Magnification: x200 when printed at 10cm.