Canes of Auer

Bone marrow aspirate showing (red arrows) blasts with Auer rods.

Auer rods are inclusions that are stained in the cytoplasm of granulocyte precursors. They consist of granular material, composed of fused lysosomes containing peroxidase, lysosomal enzymes and crystals, and which are stained with p to lapis lazuli. Typically, they appear characteristically in myeloblasts of acute myeloid leukemia, especially those of type M1, M2, M3 and M4. The eponym comes from the American physiologist John Auer (1875-1948).

wiki