Ewing's sarcoma characteristically presents in which decade of life, and the chromosomal translocation considered pathognomonic is:

• A First decade; t(8;21) RUNX1-RUNX1T1
• B Third to fourth decade; t(9;22) Philadelphia chromosome
• C First decade; t(2;13) PAX3-FOXO1 fusion
• D Second decade; t(11;22) creating EWS-FLI1 fusion gene ✓

Explanation

Ewing's sarcoma predominantly affects the second decade (5–25 years). The pathognomonic translocation t(11;22)(q24;q12) produces the EWS-FLI1 fusion gene in approximately 85% of cases; variant translocations include t(21;22) EWS-ERG. This fusion gene drives aberrant transcription factors responsible for the small round blue cell tumor phenotype. RUNX1-RUNX1T1 is in AML (M2); Philadelphia chromosome t(9;22) is in CML/ALL; PAX3-FOXO1 is in alveolar rhabdomyosarcoma.

Reference: Maheshwari Essential Orthopaedics, 6th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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