Non-Hodgkin lymphomas, the most common form of the disease, has about about 61 known types. Unlike Hodgkin lymphoma, Non-Hodgkin lymphoma does not involve Reed-Sternberg cells. It is difficult to compile all types of Non-Hodgkin lymphoma because of the great amount of time it takes to differentiate and the different methods used to do so. Therefore, the current standard classification is defined by the World Health Organization based on its appearance when analyzed under a microscope, the chromosome features of the lymphoma cells, the existence of certain proteins, and whether it is originated in B-cells or T-cells.
