Lymphoma
Lymphomas originate in lymphatic cells of the lymphoid system. The main types of cells are T lymphocytes and B lymphocytes (see Figure .1). The lymphomas are divided into Hodgkin lymphoma and non-Hodgkin lymphoma. This division is for historical reasons; Hodgkin lymphoma is caused by an abnormal B lymphocyte that is easily recognized under a microscope. These cells are called Reed-Sternberg cells. There are several subtypes of Hodgkin lymphoma, but they are all malignant.
All other lymphomas are referred to as non-Hodgkin lymphomas. A large number of different non-Hodgkin lymphomas exist. The most common types are diffuse large Bcell lymphoma (DLBCL), which constitutes about 31% of all lymphomas, and follicular lymphoma (FL), which constitutes about 22% of all lymphomas. The two related diseases, chronic lymphocytic leukemia (CLL) and small lymphocytic lymphoma (SLL), together account for 7% of all lymphomas.
DLBCL is curable in less than 50% of patients. Lymphoma is diagnosed by histopathological examination of the cells from a biopsy. Immunohistochemistry may be required to distinguish between the individual types of non-Hodgkin lymphoma. Non-Hodgkin lymphomas are staged according to Ann Arbor Staging Systems that divides the lymphomas into four stages according to how much they have spread in the body.
The Ann Arbor Staging System describes the spreading of the disease in stages I-IV. An International Prognostic Index has been developed that takes into account clinical observations-age, stage, spreading, performance status, and serum lactate dehydrogenase levels. It adds one point for each of the five poor prognostic factors: 0-1 means low, 2-3 means medium, and 4-5 means high risk.
The treatment of non-Hodgkin lymphoma follows the standard cancer therapies like radiation therapy, chemotherapy, immunotherapy, and bone marrow transplantation.