Pleural Infiltration in Atypical Chronic Myeloid Leukemia topoietic cells of the erythroid, myeloid, and megakaryocytic cells, although one lineage can predominate (6). A fourth mechanism causing effusion is nonmalignant causes, such as infection. Therefore, the possibility of infectious process must be excluded and the presence of necrotic debris and/or the positive identification of microorganisms by special stains may suggest an infectious process. Based on a review of the literature and clinical findings, leukemic infiltration into pleura was suggested as the cause of pleural effusion in our patient. Generally the median time from diagnosis of extramedullary blast crisis to marrow blast crisis is 4 months, and the medi- an survival after development of extramedullary transforma- tion is 5 months (4). Extramedullary disease in CML is con- sidered an indicator of poor prognosis, which should lead to a change in therapy and to the institution of treatments usu- ally reserved for blast crisis (4). Unfortunately, however, there is no effective standard therapy for pleural effusion in CML. To the best of our knowledge, there have been only 8 case reports of isolated pleural infiltration of CML (2-4, 7-10). One patient responded to thoracentesis and treatment with hydro- xyurea without recurrence (9), and another patient responded to systemic chemotherapy with idarubicin and Ara-C (10). In 5 patients, in which pleural blast antedated hematologi- cal transformation, intrapleural infusion of chemotherapeu- tic agents (methotrexate, cytosine arabionside, prednisone) and systemic chemotherapy were ineffective, and all 5 patients died within 2 months (3, 4, 7, 8). In the remaining patient, the type of treatment was not reported (2). In conclusion, patients with CML should be considered at risk for development of extramedullary manifestations of blast crisis while the bone marrow remains in the chronic phase. Extramedullary blast crisis of CML can occur at any time and anywhere circulating stem cells are found. In CML patient with pleural effusions, bleeding into pleural cavity and ext- ramedullary hematopoiesis should first be considered. If these causes are ruled out, the presence of leukemic cells in the effu- sion may denote leukemic involvement of pleura. Pleural infil- 939 tration of CML adversely affects prognosis. REFERENCES 1. Misialek MJ, Pechet L. A diagnostic dilemma: chronic myelomono- cytic leukemia versus atypical chronic myeloid leukemia. A case report and review of the literature. Acta Haematol 1997; 98: 221-7. 2. Jones TI. Pleural blast crisis in chronic myelogenous leukemia. Am J Hematol 1993; 44: 75-6. 3. Yam LT. Granulocytic sarcoma with pleural involvement. Identifi- cation of neoplastic cells with cytochemistry. Acta Cytol 1985; 29: 63-6. 4. Sacchi S, Temperani P, Selleri L, Zucchini P, Morselli S, Vecchi A, Longo R, Torelli G, Emilia G, Torelli U. Extramedullary pleural blast crisis in chronic myelogenous leukemia: cytogenetic and molec- ular study. Acta Haematol 1990; 83: 198-202. 5. Janckila AJ, Yam LT, Li CY. Immunocytochemical diagnosis of acute leukemia with pleural involvement. Acta Cytol 1985; 29: 67-72. 6. Suh YK, Shin HJ. Fine-needle aspiration biopsy of granulocytic sar- coma: a clinicopathologic study of 27 cases. Cancer 2000; 90: 364- 72. 7. Vilpo JA, Dryzun B, Klemi P, Lassila O, de la Chapelle A. Extra- medullary pleural blast crisis during otherwise chronic phase in chro- nic granulocytic leukaemia. Eur J Cancer 1980; 16: 885-91. 8. Scully RE, Galdabini JJ, McNeely BU. Case records of the Massa- chusetts General Hospital. Weekly clinicopathological exercises. Case 24-1976. N Engl J Med 1976; 294: 1333-9. 9. Mohapatra MK, Das SP, Mohanty NC, Dash PC, Bastia BK. Haemo- pericardium with cardiac tamponade and pleural effusion in chronic myeloid leukemia. Indian Heart J 2000; 52: 209-11. 10. Beyazit Y, Aksu S, Kekilli M, Haznedaroglu IC, Kilickap S, Goker H. Unusual extramedullary relapses under imatinib mesylate treat- ment in chronic myeloid leukemia. Am J Hematol 2005; 79: 79-80. 11. Aleem A, Siddiqui N. Chronic myeloid leukemia presenting with extramedullary disease as massive ascites responding to imatinib mesylate. Leuk Lymphoma 2005; 46: 1097-9.