Which leukemia is most common in children?

• A. ALL
• B. AML
• C. CLL
• D. CML

Answer: (A)

In children, the most common leukemia is acute lymphoblastic leukemia. This reflects that malignant transformation most often involves lymphoid precursor cells in the bone marrow, causing a large proportion of pediatric leukemias to be ALL. The result is a buildup of lymphoblasts that crowds out normal blood cell production, leading to fatigue, infections, and bruising from marrow suppression.

Another type, acute myeloid leukemia, does occur in kids but is less frequent than ALL and becomes more common with age. The chronic leukemias (chronic lymphocytic leukemia and chronic myeloid leukemia) are predominantly diseases of adults and are rare in children. So ALL stands out as the most common leukemia in the pediatric population.