Chonic leukemia. Chronic leukemia in general can be divided in to chronic lymphocyic leukemia (cll) or chronic myelogenous leukemia (cml).. Boh are usually in adult. Median age a diagnosis in CML is 50 yrs; and in cll is 70 yrs. Cll accounts for 30% leukemia case -which is the most common leukemia in western countries. CML accounts for 15-20% cases. Most common presentation for both are abnormal blood test.