Which virus is implicated in Burkitts lymphoma? (E. REPEAT 2013)
High-Yield Explanation
Ref: Robbins Pathologic Basis of Disease. 8th edition. Pages 607 and 314Explanation:BURKITT LYMPHOMAThere are three clinical types:African (endemic) Burkitt lymphoma.Sporadic (nonendemic) Burkitt lymphoma.Aggressive lymphomas associated with HIV. These 3 types are histologically identical.MorphologyThe tumor exhibits a high mitotic index and contains numerous apoptotic cells, the nuclear remnants of which are phagocytosed by interspersed benign macrophages.These phagocytes have abundant clear cytoplasm, creating a characteristic "starry sky" pattern.ImmunophenotypeThese are tumors of mature B cells.It express surface IgM, CD 19, CD20, CD 10 and BCL6. a phenotype consistent with a germinal center B-cell origin.Unlike other tumors of germinal center origin, this does not express anti-apoptotic protein BCL2.Molecular PathogenesisAll forms of Burkin lymphoma are associated with translocations of the c-MYC gene on chromosome 8.The translocation partner is usually the IgH locus light-chain loci.All endemic tumors are latently infected with EBV. which is also present in about 25% of HIV- associated tumors and 15% to 20% of sporadic cases.Clinical FeaturesEndemic Burkitt lymphoma often presents as a mass involving the mandible and shows an unusual predilection for involvement of abdominal viscera, particularly the kidneys, ovaries and adrenal glands.Sporadic Burkitt lymphoma most often appears as a mass involving the ileocecum and peritoneum.Burkitt lymphoma is very aggressive but responds well to intensive chemotherapy.