Which finding is characteristic of acute myeloid leukemia on bone marrow examination?

• A. Auer rods
• B. Heinz bodies
• C. Bence-Jones proteins
• D. Reed-Sternberg cells

Answer: (A)

Auer rods are the defining clue for acute myeloid leukemia on bone marrow examination. These are needle-like inclusions within myeloblasts that consist of azurophilic granules rich in myeloperoxidase, reflecting a myeloid lineage. Their presence confirms that the proliferating blasts are of myeloid origin, which differentiates AML from lymphoid leukemias. Because these rods are myeloperoxidase-positive, they stain with specific cytochemical stains and are not seen in other hematologic malignancies. In contrast, the other options point to entirely different conditions: Heinz bodies occur with oxidative damage to hemoglobin, Bence-J Jones proteins with plasma cell disorders like multiple myeloma, and Reed-Sternberg cells with Hodgkin lymphoma.