Immunodeficiency-associated Burkitt lymphoma is usually associated with HIV infection, but can also occur in the setting of post-transplant patients.Burkitt lymphoma is commonly associated with the infection of B cell lymphocytes with the EBV and in these cases is considered to be one form of the Epstein–Barr virus-associated lymphoproliferative diseases. The endemic variant of Burkitt lymphoma is in almost all cases associated with EBV infection. The fact that some Burkitt lymphoma cases do not involve EBV allows that many cases of the disease are not caused and/or promoted by EBV, i.e. the virus may be an innocent passenger virus in these cases. However, the almost ubiquitous presence of the virus in the endemic variant of Burkitt lymphoma suggests that it contributes to the development and/or progression of this variant. The mutational landscape in Burkitt lymphoma has recently been found to differ between tumors with and without EBV infection, further strengthening the role of the virus in disease origin. Pathophysiology
Genetics
All types of Burkitt lymphoma are characterized by dysregulation of the c-myc gene by one of three chromosomal translocations. This gene is found at 8q24. The most common variant is t(8;14)(q24;q32), which accounts for about 85% of cases. This involves c-myc and IGH@. A variant of this, a three-way translocation, t(8;14;18), has also been identified. A rare variant is at t(2;8)(p12;q24). This involves IGK@ and c-myc. Another rare variant is t(8;22)(q24;q11).
Epidemiology
As a non-Hodgkin lymphoma (NHL), Burkitt lymphoma makes up 1-5% of cases, and it is more common in males than females with a 3–4 to 1 ratio. The endemic variant mainly impacts areas with an increased prevalence of malaria and EBV in Africa and Papua New Guinea. For children less than 18 years of age from equatorial Africa, the annual incidence of Burkitt lymphoma is 4–5/100,000. Additionally, in equatorial Africa, 50% of tumors that are diagnosed during childhood as well as 90% of lymphoma cases can be attributed to Burkitt lymphoma. The peak incidence for endemic Burkitt lymphoma is from ages 4 to 7 with an average age of 6 years. The sporadic variant with an annual incidence 2-3/million is more commonly found in North America and Europe comprising 1-2% of adult lymphomas and 30–40% of NHL cases. This variant is 3.5 times more commonly found in males compared to females and it is more frequent in younger individuals. The sporadic variant has a peak incidence at 11 years of age in children, and diagnosis typically occurs from 3–12 years of age on average. For adults, 45 years was the median age that the sporadic Burkitt lymphoma was diagnosed. The immunodeficiency-associated variant predominantly impacts the HIV-infected population. For those in the United States and with AIDS, the incidence of this variant was found to be 22/100,000 person-years.