Leukemias are cancers of the blood-forming tissues, leading to an overproduction of abnormal white blood cells. Histological examination of bone marrow aspirates and peripheral blood smears reveals the presence of immature and atypical cells. For example, in AML, myeloblasts with Auer rods (needle-like inclusions) are often observed. In chronic lymphocytic leukemia (CLL), an increased number of small, mature-appearing lymphocytes with a characteristic "smudge cell" appearance is noted.
