ABSTRACT
Burkitt lymphoma (BL) is an aggressive B-cell lymphoma with a mature germinal center B-cell phenotype characterized by a bulky disease, common extranodal location, high degree of proliferation (Ki-67 index approaching 100%), frequent leukemic presentation, and deregulation of the MYC gene most often due to t(8;14)(q24.1;q32) [1–6]. It can present as lymphoma or leukemia. Three epidemiologic variants of BL are recognized: (1) endemic, (2) sporadic (spontaneous), and (3) associated with immunodeficiency (HIV). Adult patients with sporadic or immunodeficiency-associated BL typically present with extranodal disease. The endemic variant is most often observed in children aged 4 to 7 with frequent involvement of the mandible and maxilla and abdominal organs, especially the kidneys. Fifteen percent present with sudden paraplegia and incontinence. Bone marrow (BM) involvement is rare. BL is associated with malaria endemicity, and Epstein-Barr virus (EBV) is found in almost all cases. Sporadic BL occurs mainly in older children and young adults and presents as abdominal disease (60–80%), followed by the head and neck, including the lymph nodes, oropharynx, tonsils, and sinuses. Involvement of the jaw is rare. A significant subset of BL is associated with EBV infection (endemic and HIV-associated forms). A leukemic phase can be observed in patients with bulky disease, but only rare cases present purely as leukemia with blood and BM involvement. With the current chemotherapy regimens, the overall survival rate is approximately 90% in children and 50% to 70% in adults [7–10]. An algorithmic approach to the diagnosis of BL and high-grade B-cell lymphomas is presented in Figure 16.1 and Figure 2.8 (Chapter 2).
