Burkitt lymphoma is a cancer of the lymphatic system, particularly B lymphocytes found in the germinal center. It is named after Denis Parsons Burkitt, the Irish surgeon who first described the disease in 1958 while working in equatorial Africa. The overall cure rate for Burkitt lymphoma in developed countries is about 90%, and it is worse in low-income countries. Burkitt lymphoma is uncommon in adults, in whom it has a worse prognosis. Classification
Burkitt lymphoma can be divided into three main clinical variants: the endemic, the sporadic, and the immunodeficiency-associated variants. By morphology (i.e., microscopic appearance), immunophenotype, and genetics, the variants of Burkitt lymphoma are alike. The endemic variant (also called "African variant") most commonly occurs in children living in malaria-endemic regions of the world (e.g., equatorial Africa, Brazil, and Papua New Guinea). Epstein–Barr virus (EBV) infection is found in nearly all patients. Chronic malaria is believed to reduce resistance to EBV, allowing it to take hold. The disease characteristically involves the jaw or other facial bone, distal ileum, cecum, ovaries, kidney, or breast. The sporadic type of Burkitt lymphoma (also known as "non-African") is the most common variant found in places where malaria is not prevalent such as North America and parts of Europe. The tumor cells have a similar appearance to the cancer cells of classical endemic Burkitt lymphoma. Sporadic lymphomas are rarely associated with the EBV. The jaw is less commonly involved in this variant. The abdominal region is the common site of involvement.
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.