Lymphoma. Coloured scanning electron micrograph (SEM). Hodgkin lymphoma. The hallmark of this subtype is small number of Hodgkin and Reed-Sternberg (HRS) cells scattered in a sea of small lymphocytes. A single Reed- Sternberg cell is seen center. Some red blood cells and other white blood cells are also seen. Hodgkin's lymphoma is a type of cancer that begins in your lymphatic system, which is part of the body's germ-fighting immune system. In Hodgkin's lymphoma, white blood cells called lymphocytes grow out of control, causing swollen lymph nodes and growths throughout the body. The other general category of lymphoma is non- Hodgkin's lymphoma. Magnification: x4000 when printed at 10 centimetres wide.