A 40-year-old man presents with fatigue and bleeding gums. Examination shows marked gingival hypertrophy and violaceous skin nodules. Bone marrow reveals 45% blasts that are strongly positive for nonspecific esterase and negative for myeloperoxidase. Which FAB subtype and cytogenetic association fits this case?
- A AML M3, associated with t(15;17)
- B AML M5, associated with abnormalities involving 11q23 ✓
- C AML M6, associated with del(5q)
- D AML M7, associated with Down syndrome
Correct answer: B. AML M5, associated with abnormalities involving 11q23
Explanation
Gingival and skin infiltration by leukemic cells plus nonspecific esterase positivity identifies acute monocytic leukemia, FAB M5. M5 is classically associated with translocations involving the KMT2A (formerly MLL) gene at chromosome band 11q23, particularly in infants and after topoisomerase II inhibitor exposure. M3 presents with DIC rather than tissue infiltration, M6 is erythroid, and M7 is megakaryocytic and linked to Down syndrome.
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.