A 10-year old boy was presented with a mass in abdomen. On imaging, the para-aoic lymph nodes were enlarged. On biopsy, starry sky appearance was seen. What is the underlying abnormality?
p53 gene mutation
Rb gene mutation
Translocation involving BCR-ABL gene
Translocation involving Myc gene
Ans: D. Translocation involving Myc geneStarry eye pattern on biopsy - Highly suggestive of Burkitt lymphoma.All forms of Burkitt lymphoma associated with translocations of c-MYC gene on chromosome 8.Burkitt lymphoma:Tumor exhibiting high mitotic index & contains numerous apoptotic cells.Nuclear remnants of apoptopic cells are phagocytosed by interspersed benign macrophages.These phagocytes with abundant clear cytoplasm, creating a characteristic "starry sky" pattern."Etiology:All forms of Burkitt lymphoma are associated with translocations of c-MYC gene on chromosome S.Genetic mutation & associated conditions:TranslocationGene (Chromosome)Malignancy(9;22) (q34;q11)ABL-BCRChronic myeloid leukemia(11;14)(q13;q32)BCL1-IgHMantle cell lymphoma(8;21)RUNX1-RUNX1T1 (15;17)PML-RARAAcute myeloid leukemia(16;16)CBFB-MYH11 (11;22)(q24;q12)FLII-EWSEwing's sarcoma(8;14)(q24;q32)MYC-IgHBurkitt's lymphoma B cell acute lymphocytic leukemiaInv (2p13;p11.2-14)REL-NRGNon-Hodgkin's lymphoma(1;3)(p34;p21)TAL1-TCTAQAcute T cell leukemia(Ref: Robbins 9/e p597)