medical Definition of acute lymphoblastic leukemia
: lymphocytic leukemia that is marked by an abnormal increase in the number of lymphoblasts, that is characterized by rapid onset and progression of symptoms which include fever, anemia, pallor, fatigue, appetite loss, bleeding, thrombocytopenia, granulocytopenia, bone and joint pain, and enlargement of the lymph nodes, liver, and spleen, and that occurs chiefly during childhood
—abbreviation ALL
— compare chronic lymphocytic leukemia
