Auer rods (or Auer bodies)
Auer rods (or Auer bodies) –

Large, crystalline cytoplasmic inclusion bodies
Observed in myeloid blast cells in cases of :
- Acute myeloid leukemia,
- Acute promyelocytic leukemia,
- High-grade myelodysplastic syndromes
- Myeloproliferative disorders
- Composed of fused lysosomes and rich in lysosomal enzymes,
Auer rods are azurophilic and can resemble needles, commas