Burkitt Lymphoma : Ki-67

Burkitt's lymphoma is a highly aggressive B-cell neoplasm which often involves extranodal sites or presents as a leukemia. It consists of a monomorphic population of B-cells with basophilic cytoplasm and a high mitotic rate. The tumor cells show translocations on chromosome 8 at 8q24 involving the MYC oncogene.Three variants of Burkitt's lymphoma have been recognized. They are morphologically similar (with subtle variations) but differ in their clinical features, molecular genetics, and virologic characteristics. 1) Endemic Burkitt's Lymphoma : This variant is endemic in the malaria belt of sub-Saharan Africa around the equatorial region. It affects mainly young children (4 to 10 years old) with 2:1 male:female ratio. The sites commonly involved are jaw, facial bones, and the orbit. Most cases are positive for Epstein-Barr virus (EBV). 2) Sporadic Burkitt's Lymphoma : It is seen throughout the world and mainly affects children and young adults with a male predominance (male:female = 2-3:1). It accounts for 30% to 50% of pediatric lymphomas. The most commonly affected site is gastrointestinal tract. Positivity for EBV is seen in 15% to 20% of cases. 3) Burkitt's Lymphoma associated with Immunodeficiency: This form is usually seen in association with HIV infection but may also occur with other immunodeficient states such as congenital disorders and following organ transplantation. About 25% of cases are EBV-positive. The tumor cells may show plasmacytoid differentiation.