A 42-year-old woman presents with gum bleeding, petechiae, and fatigue. Hemoglobin 7.8 g/dL, platelets 18,000/µL, WBC 22,000/µL with abnormal promyelocytes containing numerous Auer rods bundled as 'faggot cells'. PT and aPTT are prolonged with fibrinogen of 90 mg/dL. Which cytogenetic abnormality defines this condition?
- A t(9;22)(q34;q11) producing BCR-ABL1
- B inv(16)(p13;q22) producing CBFbeta-MYH11
- C t(15;17)(q24;q21) producing PML-RARA ✓
- D t(8;21)(q22;q22) producing RUNX1-RUNX1T1
Correct answer: C. t(15;17)(q24;q21) producing PML-RARA
Explanation
Acute promyelocytic leukemia is defined by t(15;17), which fuses PML on chromosome 15 to RARA on 17, generating the PML-RARA fusion that blocks myeloid differentiation at the promyelocyte stage. The presentation with DIC and faggot cells is classic. inv(16) and t(8;21) are favorable-risk core binding factor AMLs seen in other morphologic subtypes, while t(9;22) defines CML and Ph-positive ALL.
Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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