A 40-year-old man presents with fatigue and gingival bleeding. Marrow shows a myelomonocytic proliferation with numerous abnormal eosinophils containing large basophilic-purple granules. Which cytogenetic abnormality should be sought, and what is its prognostic implication?
- A inv(16) forming CBFB-MYH11, a favourable-risk core-binding-factor leukaemia ✓
- B Trisomy 8, adverse prognosis requiring allogeneic transplant upfront
- C t(15;17), favourable prognosis with retinoid-based therapy
- D Complex karyotype with monosomal abnormalities, intermediate prognosis
Correct answer: A. inv(16) forming CBFB-MYH11, a favourable-risk core-binding-factor leukaemia
Explanation
Myelomonocytic blasts with dysplastic eosinophils bearing large basophilic granules define AML-M4Eo, caused by inv(16), which fuses CBFB to MYH11 and disrupts the core-binding factor transcription complex. Along with t(8;21), it belongs to the favourable-risk group, where intensive chemotherapy achieves high remission rates. The distractor t(15;17) characterizes acute promyelocytic leukaemia with uniform promyelocytes, not eosinophil dysplasia, although it too carries a good prognosis.
Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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