A 32-year-old man presents with fatigue and abdominal discomfort. Peripheral smear shows blasts with monocytic features along with mature and immature eosinophils, some containing large basophilic-violet granules. Bone marrow confirms AML with 30% blasts. Which cytogenetic abnormality should be sought?

• A trisomy 8 as the sole abnormality
• B t(15;17)(q24;q21) forming PML-RARA
• C del(5q)
• D inv(16)(p13.1q22) forming CBFB-MYH11 ✓

Explanation

AML with inv(16)(p13.1q22), which creates the CBFB-MYH11 fusion gene, corresponds to acute myelomonocytic leukemia with abnormal eosinophils (formerly FAB M4Eo). The abnormal eosinophils contain large basophilic granules due to chimeric proteins stored in their granules. Like t(8;21), it disrupts the core binding factor complex and carries a relatively favorable prognosis. PML-RARA lacks monocytic differentiation, and del(5q) defines a poor-risk entity.

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.