A 40-year-old woman with de novo AML has a bone marrow showing 32% blasts with monocytic differentiation and numerous abnormal eosinophils with large basophilic-purple granules. Cytogenetic analysis would most likely reveal which favourable prognostic abnormality?

• A Complex karyotype with three or more unrelated abnormalities
• B Monosomal karyotype with loss of chromosome 7
• C inv(16)(p13.1q22) forming CBFB-MYH11 fusion ✓
• D t(6;9)(p23;q34) forming DEK-NUP214 fusion

Explanation

Acute myelomonocytic leukaemia with abnormal eosinophils is FAB M4Eo, caused by inv(16) generating the CBFB-MYH11 fusion that disrupts core binding factor; it defines the favourable risk core binding factor group along with t(8;21) RUNX1-RUNX1T1. Monosomal and complex karyotypes are the worst prognostic categories, and t(6;9) DEK-NUP214 is an intermediate to poor risk lesion frequently associated with FLT3-ITD, so none of these carry favourable outcomes.

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.