A 52-year-old man presents with fatigue, early satiety, and left upper quadrant discomfort. Examination reveals massive splenomegaly. CBC shows hemoglobin 9.8 g/dL, WBC 145,000/µL with myelocytes, metamyelocytes, and basophils on differential, and platelets 620,000/µL. Leukocyte alkaline phosphatase score is low. Which genetic abnormality is most likely present?
- A t(15;17)
- B t(8;14)
- C t(9;22) ✓
- D inv(16)
Correct answer: C. t(9;22)
Explanation
The presentation is classic chronic myeloid leukemia: leukocytosis with left shift and basophilia, thrombocytosis, splenomegaly, and low LAP score. The t(9;22) translocation producing the BCR-ABL fusion gene (Philadelphia chromosome) is the molecular hallmark of CML and is present in over 95% of cases. t(15;17) is seen in acute promyelocytic leukemia.
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.