Lymphoma. Coloured scanning electron micrograph SEM of lymphoma cancer cells yellow in a lymph node. Some red blood cells are also seen. The cells are surrounded by a connective tissue capsule purple. Lymphoma is a malignant cancerous growth of white blood cells lymphocytes. White blood cells are part of the body磗 immune system and circulate in a clear liquid called lymph. There are many types of lymphoma depending on the cells affected. All lymphomas however, are divided into 2 types, Hodgkin磗 and non_Hodgkin磗 lymphomas. Hodgkin磗 lymphoma is characterised by the presence of Reed_ Sternburg cells, a giant type of macrophage. All other lymphomas are non_Hodgkin磗.