Which is a characteristic feature of Auer rods?

Auer rods are indeed characterized by being composed of azurophilic granules. These granules are formed from the fusion of cytoplasmic granules in myeloid cells and are indicative of myeloid lineage. Their presence is a distinguishing feature of acute myeloid leukemia (AML) and is often used to help diagnose this condition.

The structural composition of Auer rods is significant because it can signify a more immature and undifferentiated state of hematopoietic cells, which is crucial for diagnosing different types of leukemias. In the context of clinical significance, finding Auer rods in the peripheral blood or bone marrow confirms that the abnormal cells are of myeloid origin, reinforcing the diagnosis of myeloid leukemias.

Other options, while relevant to hematology, do not accurately describe Auer rods. For instance, while periodic acid-Schiff (PAS) positivity can occur in some leukemias, it is not a defining characteristic of Auer rods. Auer rods are not predominantly associated with chronic myelogenous leukemia; instead, they are more commonly found in acute types. Lastly, while nonspecific esterase positivity can be relevant in the context of certain hematologic malignancies, Auer rods are