A 32-year-old woman presents with gum bleeding, petechiae, and fever. CBC shows WBC 34,000/µL, hemoglobin 8 g/dL, platelets 18,000/µL. PT and aPTT are prolonged, fibrinogen is 90 mg/dL, and D-dimer is markedly elevated. Bone marrow shows promyelocytes with numerous Auer rods arranged in bundles. What is the first-line specific therapy?
- A Imatinib
- B Hydroxyurea
- C All-trans retinoic acid ✓
- D Rituximab
Correct answer: C. All-trans retinoic acid
Explanation
The picture is acute promyelocytic leukemia (AML M3) with disseminated intravascular coagulation. The t(15;17) translocation creates the PML-RARA fusion protein, which blocks myeloid differentiation. All-trans retinoic acid binds the fusion receptor and forces terminal maturation of promyelocytes, and it also rapidly corrects the coagulopathy. Imatinib targets BCR-ABL in CML and Ph+ ALL, not PML-RARA, so it has no role here.
Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.