A 32-year-old woman presents with fatigue, gingival bleeding, and ecchymoses. Peripheral blood shows pancytopenia with 60% abnormal promyelocytes containing bundles of Auer rods and heavy granulation. Coagulation studies reveal a prolonged PT and low fibrinogen. Which specific chromosomal translocation is most likely to be found?
- A t(8;21)(q22;q22)
- B inv(16)(p13q22)
- C t(15;17)(q24;q21) ✓
- D t(9;22)(q34;q11)
Correct answer: C. t(15;17)(q24;q21)
Explanation
The clinical picture is classic for acute promyelocytic leukemia (APL, AML-M3): abnormal promyelocytes with faggot cells (bundles of Auer rods), DIC with hypofibrinogenemia, and bleeding diathesis. The pathognomonic translocation is t(15;17), which produces the PML-RARα fusion protein. This fusion blocks myeloid differentiation and is the target of all-trans retinoic acid (ATRA) therapy. t(8;21) is seen in AML-M2, inv(16) in AML-M4Eo, and t(9;22) in CML.
Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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