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Burkitt's lymphoma

Burkitt's lymphoma (or "Burkitt's tumor", or "Malignant lymphoma, Burkitt's type") is a cancer of the lymphatic system (in particular, B lymphocytes). It is associated with the Epstein-Barr virus, also the cause of mononucleosis as well as other cancers. It is named after Denis Parsons Burkitt, a surgeon who first described the disease in 1956 while working in equatorial Africa.

Children affected with the disease often also had chronic malaria which is believed to have reduced resistance to the virus. This is known as classical African or endemic Burkitt's lymphoma. Disease characteristics include large tumors in the facial or abdominal regions.

Outside of central Africa, a type of non-Hodgkin lymphoma is found where cancer cells have a similar appearance to the cancer cells of classical African or endemic Burkitt's lymphoma. This condition is known as the non-African or sporadic type of Burkitt's lymphoma. Again it is believed that impaired immunity provides an opening for development of the Epstein-Barr virus. Examination of chromosomes in this tumor shows translocation of the myc gene with an Ig gene is seen in this lymphoma, commonly.

Classification

Currently 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[3] 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.

Epidemiology

Of all cancers involving the same class of blood cell, 2% of cases are Burkitt's lymphoma.[4]

Microscopy

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[5] 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.

Malignant B cell characteristics

Malignant B cells have identical DNA recombinations of the V(D)J region of the Immunoglobin genes. This means that no increase in specificity of Antibody molecules is occurring in the malignant cells. These malignant cells are thus clonal populations and can be assayed for by using DNA probes specific for the regions where recombination is expected. Normal DNA will be characterized by two high concentration of identical germ line DNA V(D)J regions and endless, likely undetectable, non-germline Ig V(D)J DNA. Lymphoma cells have an additional high concentration of V(D)J DNA that is unlike the germline, indicating clonal populations of B Cells that are not undifferentiated B Cells (Germline DNA cells). Assays typically use the process of Electrophoresis and southern blot analysis to determine the existence of these characteristics.

Treatment

Treatment includes dose-adjusted EPOCH with Rituxan (rituximab).[9]

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.

• Chemotherapy
• cyclophosphamide
• doxorubicin
• vincristine
• methotrexate
• cytarabine
• ifosfamide
• etoposide
• rituximab[10]

Other treatments are immunotherapy, bone marrow transplants, surgery to remove the tumor, and radiotherapy.

Prognosis

Treatment with dose-adjusted EPOCH with Rituxan (rituximab) has shown an 8 year survival rate of 91% for low risk, 90% for low-intermediate risk, 67% for high-intermediate risk, and 31% for high risk cases with few of the side effects associated with Burkitt's lymphoma chemotherapy.[9]

References

1. synd/2511 at Who Named It?
2. Burkitt D (1958). "A sarcoma involving the jaws in African children". The British journal of surgery 46 (197): 218–23. doi:10.1002/bjs.18004619704. PMID 13628987.
3. Bellan C, Lazzi S, De Falco G, Nyongo A, Giordano A, Leoncini L (March 2003). "Burkitt's lymphoma: new insights into molecular pathogenesis". J. Clin. Pathol. 56 (3): 188–92. doi:10.1136/jcp.56.3.188. PMC 1769902. PMID 12610094.
4. Turgeon, Mary Louise (2005). Clinical hematology: theory and procedures. Hagerstown, MD: Lippincott Williams & Wilkins. pp. 283. ISBN 0-7817-5007-5. "Frequency of lymphoid neoplasms. (Source: Modified from WHO Blue Book on Tumour of Hematopoietic and Lymphoid Tissues. 2001, p. 2001.)"
5. Fujita S, Buziba N, Kumatori A, Senba M, Yamaguchi A, Toriyama K (May 2004). "Early stage of Epstein-Barr virus lytic infection leading to the "starry sky" pattern formation in endemic Burkitt lymphoma". Arch. Pathol. Lab. Med. 128 (5): 549–52. doi:10.1043/1543-2165(2004)128<549:ESOEVL>2.0.CO;2. PMID 15086279. 6.. ISBN 9789283224310.
6. Liu D, Shimonov J, Primanneni S, Lai Y, Ahmed T, Seiter K (2007). "t(8;14;18): a 3-way chromosome translocation in two patients with Burkitt's lymphoma/leukemia". Mol. Cancer 6: 35. doi:10.1186/1476-4598-6-35. PMC 1904237. PMID 17547754.
7. a b Smardova J, Grochova D, Fabian P, et al. (October 2008). "An unusual p53 mutation detected in Burkitt's lymphoma: 30 bp duplication". Oncol. Rep. 20 (4): 773–8. PMID 18813817.
8. a b Wyndham H. Wilson, Kieron Dunleavy, Stefania Pittaluga, Upendra Hegde, Nicole Grant, Seth M. Steinberg, Mark Raffeld, Martin Gutierrez, Bruce A. Chabner, Louis Staudt, Elaine S. Jaffe, and John E. Janik (2008). "Phase II Study of Dose-Adjusted EPOCH-Rituximab in Untreated Diffuse Large B-cell Lymphoma with Analysis of Germinal Center and Post-Germinal Center Biomarkers". Journal of Clinical Oncology 26 (16): 2717–2714. doi:10.1200/JCO.2007.13.1391. PMC 2409217. PMID 18378569.
9. Yustein JT, Dang CV (2007). "Biology and treatment of Burkitt's lymphoma". Curr. Opin. Hematol. 14 (4): 375–81. doi:10.1097/MOH.0b013e3281bccdee. PMID 17534164.