Prolymphocytic leukemia (PL) is usually derived from B cells and shares some features with chronic lymphocytic leukemia (CLL), but it is clearly a distinct entity and defined to have more than 55% prolymphocytes. Chronic lymphocytic leukemia/prolymphocytic leukemia (CLL/PL) is a mixed type of CLL and is defined to have 11∼55% prolymphocytes with intermediate features between CLL and PL. We Experienced two different cases of leukemia PL and CLL/PL. On physical examination, PL (stage II, B) patient showed multiple cervical lymph node enlargement and 5㎝ sized splenomegaly and hepatomegaly. But CLL/PL (stage III, C) patient showed 10㎝ sized splenomegaly and no lymph node enlargement. Onimmunological phenotyping, surface markers showed 72% CD5 (+), 85% CDl9 (+), and 40% Smlg (+) in PL patient and 3% CD5 (+), 90％ CDl9 (+) and Smlg (-) in CLL/PL patient. PL patient was refractory to chlorambucil and prednisolone chemotherapy and showed poor prognosis. CLL/PL patient did not show remarkable response to chlorambucil and prednisolone therapy.

Keywords: Prolymphocytic leukemia, Chronic lymphocytic leukemia, Chronic lymphocytic leukemia/prolymphocytic leukemia