Which type of leukemia is associated with white blood cells that appear "smudged" on microscopy?

Chronic Lymphocytic Leukemia (CLL) is characterized by the presence of small, mature lymphocytes that can appear "smudged" or its cells can also be referred to as "smudge cells" when examined under a microscope. These smudge cells are a result of the fragile nature of the lymphocytes, which tend to burst during the preparation of the blood smear.

CLL is the most common type of leukemia in adults and often presents with an increased number of these small, mature lymphocytes in peripheral blood, along with symptoms like lymphadenopathy and splenomegaly. The smudge cells and their associated features can help differentiate CLL from other leukemias during microscopic examination.

In contrast, Acute Myeloid Leukemia and Acute Lymphoblastic Leukemia typically show more prominent blast cells that are not smudged. Chronic Myeloid Leukemia may show increased mature and immature granulocytes but does not characteristically have smudge cells. Thus, the distinct presence of smudge cells in CLL is a vital diagnostic hallmark that supports recognizing this particular type of leukemia.