A 40-year-old woman has fatigue and easy bruising. Bone marrow shows a mixture of myeloblasts and monoblasts along with numerous eosinophils containing large basophilic-purple granules. Cytogenetics reveal inv(16)(p13;q22). Which fusion transcript is present?
- A PML-RARA
- B CBFB-MYH11 ✓
- C RUNX1-RUNX1T1
- D BCR-ABL1
Correct answer: B. CBFB-MYH11
Explanation
inv(16) fuses CBFB at 16q22 with MYH11 at 16p13, producing the core binding factor AML subtype with abnormal eosinophils bearing large basophilic granules (formerly M4eo). RUNX1-RUNX1T1 corresponds to t(8;21), the other core binding factor lesion, and PML-RARA to t(15;17); both lack the dysplastic eosinophils that are the morphologic signature killing those distractors 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.