Definition of Burkitt Lymphoma

Burkitt lymphoma is reported by the World Health Organization as a highly aggressive B-cell lymphoma. Three clinical variants of Burkitt lymphoma are recognized (endemic, sporadic, immunodeficiency-associated), which differ in geographic distribution, clinical presentation, and association with infectious agents and cell biology. The tumor is composed by monomorphic medium-sized B-cells with basophilic cytoplasm, numerous mitotic figures, and an extremely high proliferation rate (Ki-67-index >95 %). A “starry sky” pattern is usually present, due to numerous benign macrophages that have ingested apoptotic tumor cells. Tumor cells express membrane IgM with light chain restriction and B-cell-associated antigens CD19, CD20, CD22, and CD79a. Chromosomal translocation involving MYC is the most frequent genetic feature; however, some cases lack MYC translocation. No singleparameter (such as morphology, genetic analysis, or immunophenotyping) can be used as the gold standard for the diagnosis of BL, but a combination of several diagnostic techniques is necessary