Burkitt's lymphoma (or "Burkitt's tumor", Burkitt lymphoma or "malignant lymphoma, Burkitt's type") is a cancer of the lymphatic system (in particular, B lymphocytes).
Burkitt's lymphoma can be divided into three main clinical variants: the endemic, the sporadic and the immunodeficiency-associated variants. Burkitt's lymphoma is usually associated with over 90% of AIDS cases.
The endemic variant occurs in equatorial Africa. It is the most common malignancy of children in this area. Children affected with the disease often also had chronic malaria, which is believed to have reduced resistance to Epstein-Barr virus (EBV), allowing it to take hold. The disease characteristically involves the jaw or other facial bone, distal ileum, cecum, ovaries, kidney or the breast.
The sporadic type of Burkitt lymphoma (also known as "non-African") is another form of non-Hodgkin lymphoma found outside of Africa. The tumor cells have a similar appearance to the cancer cells of classical African or endemic Burkitt lymphoma. Again it is believed that impaired immunity provides an opening for development of the Epstein-Barr virus. Non-Hodgkin lymphoma, which includes Burkitt's, accounts for 30-50% of childhood lymphoma. The jaw is less commonly involved, compared to the endemic variant. The ileo-cecal region is the common site of involvement.
Immunodeficiency-associated Burkitt lymphoma is usually associated with HIV infection or occurs in the setting of post-transplant patients who are taking immunosuppressive drugs. Burkitt lymphoma can be one of the diseases associated with the initial manifestation of AIDS.
By morphology (i.e. microscopic appearance) or immunophenotype, it is almost impossible to differentiate these three clinical variants. Immunodeficiency-associated Burkitt lymphoma may demonstrate more plasmacytic appearance or more pleomorphism, but these features are not specific.
The tumor consists of sheets of a monotonous (i.e. similar in size and morphology) population of medium size lymphoid cells with high proliferative activity and apoptotic activity. The "starry sky" appearance seen under low power is due to scattered tingible body-laden macrophages (macrophages containing dead body of apoptotic tumor cells). The old descriptive term of "small non-cleaved cell" is misleading. The tumor cells are mostly medium in size (i.e. tumor nuclei size similar to that of histiocytes or endothelial cells). "Small non-cleaved cells" are compared to "large non-cleaved cells" of normal germinal center lymphocytes. Tumor cells possess small amount of basophilic cytoplasm. The cellular outline usually appears squared off.
Almost by definition, Burkitt's lymphoma is associated with a chromosomal translocation of the c-myc gene. This gene is found at 8q24.
Treatment includes dose-adjusted EPOCH with Rituxan (rituximab).
Effect of the chemotherapy, as with all cancers, depends on the time of diagnosis. With faster growing cancers, such as Burkitt's, the cancer actually responds faster than with slower growing cancers. This rapid response to chemotherapy can be hazardous to patient, as a phenomenon called "tumor lysis syndrome" could occur. Close monitoring of patient and adequate hydration is essential during the process.
Other treatments are immunotherapy, bone marrow transplants, surgery to remove the tumor, and radiotherapy.