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Pericardial Tamponade in Chronic Myelomonocytic Leukemia

1994; Elsevier BV; Volume: 106; Issue: 3 Linguagem: Inglês

10.1378/chest.106.3.967

1931-3543

Sridhar Mani, Thomas P. Duffy,

Chronic Lymphocytic Leukemia Research

We report four eases of malignant pleuroperieardial effusions in patients with chronic phase myelomonocytic leukemia (CMML). Based on current literature, this event is rare and very poorly understood. Our cases shed light on three important clinical characteristics: (1) patients with CMML develop effusions during uncontrolled leukocytosis; (2) these effusions are very responsive to conventional chemotherapy; and (3) effusions may develop without clinical forms of disease in other sites of extramedullary hematopoiesis. We report four eases of malignant pleuroperieardial effusions in patients with chronic phase myelomonocytic leukemia (CMML). Based on current literature, this event is rare and very poorly understood. Our cases shed light on three important clinical characteristics: (1) patients with CMML develop effusions during uncontrolled leukocytosis; (2) these effusions are very responsive to conventional chemotherapy; and (3) effusions may develop without clinical forms of disease in other sites of extramedullary hematopoiesis. chronic myelomonocytic leukemia hematocrit jugular venous pulsations left ventricle pulmonary capillary wedge pressure platelet right atrium right ventricle subacute myelomonocytic leukemia We describe four patients who developed malignant pericardial tamponade and/or pleural effusion during the course of subacute (SAMML) or chronic myelomonocytic leukemia (CMML). This finding has been alluded to in prior literature; however, these cases are the first (to our knowledge) to document symptomatic pericardial effusion progressing to life-threatening pericardial tamponade requiring specific therapy. All our patients had relatively high peripheral blood monocyte counts with evidence of leukemic cells in their pericardial fluid. The effusions were exudative and serosanguineous, although only one patient had possible pericardial tissue involvement with leukemia. Once definitive treatment with hydroxyurea was instituted after the evacuation of fluid and stabilization of their cardiovascular parameters, there were no further recurrences of symptomatic pericardial effusions. Review of our cases along with cases documented in the literature point toward the possibility of an added complication; namely, serous effusions during uncontrolled leukocytosis or leukostasis in these patients. A 77-year-old woman with CMML was admitted to the hospital with a 3-week history of progressive dyspnea and fatigue.On examination she was markedly tachypneic (30/min), pale, hypotensive (90/60 mm Hg), orthostatic, and mildly dehydrated. Cardiovascular examination was significant for jugular venous pulsations (JVP) at 6 cm, the absence of Kussmaul's sign, pulsus paradoxus, pericardial friction rub, and diminished heart sounds. Pulmonary examination revealed decreased breath sounds bilaterally with dullness to percussion at the left lung base. There was moderate hepatosplenomegaly with trace bipedal pitting edema.Laboratory data revealed a white blood cell count (WBC) of 126×109/L (her baseline WBC 2 months prior was less than 10×109/L) with 38 percent segmented cells, 6 percent band cells, 5 percent lymphocytes, 37 percent monocytes, 12 percent metamyelocytes, and 2 percent blast cells. Hematocrit (Hct) was 28.5 percent with hemoglobin (Hgb) of 9.0 g/dl and platelets (Pit) of 94,000/mm3. The electrocardiogram revealed diffuse lowvoltage QRS complexes with sinus tachycardia at 100/min. Chest radiograph revealed new bilateral pleural effusions and an enlarged cardiac silhouette.After admission to the ICU, she developed more pronounced dyspnea with a pulsus paradoxus of 20 mm Hg. Two-dimensional (2D) and M-mode echocardiogram revealed a large pericardial effusion with diastolic collapse of the right atrium and ventricle consistent with pericardial tamponade. Right heart catheterization revealed a "square root" right ventricular tracing.Serosanguineous fluid, 500 ml, was aspirated at pericardiocentesis. The intrapericardial and right atrial (RA) pressure was 20 mm Hg with preserved systolic x descent and diminished diastolic y descent. There was diastolic equalization of intrapericardial, RA, right ventricular (RV) and left ventricular (LV) pressures. Postpericardiocentesis, her intrapericardial pressure decreased to zero, right atrial pressure normalized to 4 mm Hg with reappearance of the diastolic y descent, and systemic blood pressure increased to 120 mm Hg. Follow-up echocardiograms failed to reveal reaccumulation of pericardial fluid. Fluid cytologic study was positive for myelomonocytic cells and fluid chemistry revealed a glucose level of 32 mg/dl, protein level of 4.6 g/L, and lactate dehydrogenase (LDH) level of 1,300 U/dl. Shortly after her pericardiocentesis, she received hydroxyurea at doses ranging from 500 to 1,000 mg/d with maintenance of her WBC between 45 and 50×109/L. Two and one half years after initial treatment, she remains well without any recurrence of pericardial effusions. A 60-year-old man with CMML was admitted to the hospital with a 1-week history of pleuritic chest pain radiating to the neck and progressive fatigue and dyspnea. Until 3 weeks prior to this admission, he had stable WBC in the range 15 to 20,000/mm3 without blast cells.On examination, pertinent findings included an elevated JVP at 7 cm without an inspiratory accentuation, and distant heart sounds without a pericardial knock or rub. There was no pulsus paradoxus.Pertinent laboratory data included a Hgb of 10 g/dl, Hct of 31.4 percent, Pit of 96,000/mm3, WBC of 71,000/mm3 with a differential of 35 percent monocytes, 2 percent myelocytes, and 1 percent blasts. The electrocardiogram revealed persistent left anterior hemiblock and low voltage across all 12 leads. The chest radiograph and computed tomographic (CT) scan showed new enlarged cardiac silhouette with moderate pericardial and left pleural effusions. A 2D echocardiogram revealed significant pericardial effusion with diastolic collapse of the ventricles suggesting early tamponade.At initial pericardiocentesis, 700 ml of grossly hemorrhagic fluid was removed. The intrapericardial and RA pressure was 25 mm Hg with obliteration of the diastolic y descent. There was diastolic equalization of intrapericardial, RA, RV, LV, and pulmonary capillary wedge pressures (PCWP). After pericardiocentesis, the intrapericardial pressure decreased to zero; RA to 3 mm Hg; RV to 6 mm Hg; and LV to 10 mm Hg. The cardiac output index improved from 2.5 to 3.8 L/min/m2. Although he had hemodynamic improvement with better exercise tolerance, he became symptomatic within 2 days of pericardiocentesis. Subsequently, he underwent pericardial drainage removing more than 1,000 ml of grossly bloody fluid over the course of a few hours. Simultaneously, he was started on a regimen of hydroxyurea treatment that reduced his WBC from 150,000/mm3 to 16,000/mm3. A pericardial drain was inserted and there was virtually no drainage by day 2 postpericardiocentesis. The pericardial fluid was exudative and cytologic study revealed leukemic cells.After hospital discharge, he was placed on a regimen of oral etoposide (VP-16) and his condition has remained stable for 3 years thereafter. He has not had recurrence of pericardial effusions/tamponade. A 69-year-old woman with CMML presented with a 2-day history of substernal chest tightness with left shoulder pain and dyspnea. In the past, her leukemia was controlled with hydroxyurea with WBCs ranging from 50 to 80,000/mm3.On examination, she was tachypneic (35/min) with blood pressure of 100/55 mm Hg. Cardiovascular examination revealed decreased heart sounds with a faint systolic murmur at the left lower sternal border. The JVP was 3 cm and there was no pulsus paradoxus. The lungs were clear to auscultation and the liver and spleen size were normal. There were no gingival or skin lesions.The pertinent laboratory values included a WBC of 129,600/mm3 with 35 percent segmented cells, 4 percent band cells, 4 percent lymphocytes, 54 percent monocytes, and 1 percent eosinophils, and Hct was 23.5 percent. The electrocardiogram revealed diffuse low voltage with nonspecific ST segment changes in the inferolateral leads. A 2D echocardiogram revealed a large fluid-filled pericardial sac with diastolic RA and RV compression.At catheterization, the intrapericardial and RA pressures were 18 mm Hg and there was a complete obliteration of the diastolic y descent. There was mid-diastolic equalization of RA, RV, LV, and PCWP. Her tracing revealed the "square root" sign characteristic of pericardial tamponade.At pericardiocentesis, 900 ml of serosanguineous fluid was aspirated. Fluid cytologic study revealed myelomonocytic cells. A pericardial window was placed and pericardial biopsy specimen revealed fibrinous pericarditis with a focus of a few atypical monocytoid cells suspicious for leukemic infiltration. Postdrainage echocardiogram revealed minimal pericardial effusion.Two days later, while not receiving hydroxyurea, the patient developed a right-sided pleural effusion. A pleurocentesis was performed and the fluid cytologic study revealed atypical monocytoid cells suspicious for malignancy. Despite initial drainage, recurrent effusions developed requiring a chest tube. At this time, a 2D echocardiogram also revealed slight increase in the amount of pericardial effusion; however, there were no signs of early pericardial tamponade.She was restarted on hydroxyurea therapy (1.5 g/d orally) and her WBC decreased to 30,000/mm3. Follow-up chest radiograph and echocardiogram prior to hospital discharge revealed no further recurrence of pleural effusions or tamponade.Unfortunately, 2 weeks after hospital discharge she was readmitted with a WBC of 150,000/mm3 with more than 30 percent blast forms in the peripheral blood smear. She refused aggressive management of her now acute leukemic transformation and she was placed on a regimen of 6 g/d of hydroxyurea. Her leukemia was unresponsive to escalating doses of hydroxyurea, and she died of pulmonary leukostasis. An 81-year-old woman with CMML presented with a 2-week history of acute dyspnea. Two weeks before her present hospital admission, her WBC count had risen from a baseline of 30×109/L to 90×109/L despite increasing doses of hydroxyurea.On examination, she was diaphoretic, hypotensive (80/60 mm Hg), pale, and clammy. Her respirations were markedly labored (40/min). Jugular venous pulsations were prominent with inspiratory expansion of her external jugular vein. Her chest examination revealed diffuse bilateral rales throughout. The cardiovascular examination revealed distant heart sounds and a diffuse point of maximal impulse. No pulsus paradoxus could be demonstrated. Laboratory data included a WBC of 100×109/L with 50 percent myelomonocytes and 10 percent blasts. A 12-lead electrocardiogram revealed diffuse low voltage and flattened T waves. Chest radiograph revealed a markedly enlarged cardiac silhouette and congestive heart failure.She was admitted to the ICU and was treated with intravenous furosemide, morphine sulfate, and dopamine. She required daily packed red blood cells to maintain her Hct greater than 25 percent and Pit transfusion to maintain Pit greater than 20,000/mm3. An emergent echocardiogram revealed a moderate size anterior pericardial effusion but no evidence of tamponade. Four hours later, her blood pressure dropped (60/40 mm Hg) and she was started on a regimen of intravenous dobutamine. A repeated echocardiogram revealed increased pericardial effusions with diastolic right and left atrial collapse. Pericardiocentesis revealed 600 ml of serosanguineous fluid. Although the blood pressure increased to 90/60 mm Hg postopericardiocentesis, she continued to require dobutamine and dopamine. At this point, her WBC had risen to over 145×109/L and she was started on a regimen of hydroxyurea at 500 mg/d that reduced the WBC to 90×109/L in 6 h. Sixteen hours after decreasing her WBC count, her systolic BP remained stable at 100 mm Hg requiring only dopamine. Unfortunately, 48 h later, the patient developed acute polymicrobial sepsis (Acinetobacter, Streptococcus) resistant to all pharmacologic agents, and she died soon thereafter. Chronic myelomonocytic leukemia, a subclassification of a broader category of myelodysplastic syndrome, is characterized by a peripheral monocyte count greater than 1×109/L, a peripheral blood blast cell percentage less than 5 percent, a bone marrow blast cell percentage less than 20 percent, and a noted absence of Auer rods.1Bennett JM Catovsky D Daniel MT Flandrin G Galton DAG Gralnich HR et al.The French-American-British (FAB) Cooperative Group: proposals for the classification of the myelodysplastic syndromes.Br J Haematol. 1982; 51: 189-199Crossref PubMed Scopus (3705) Google Scholar, 2Tefferi A Hoagland HC Therneau TM Pierre RV Chronic myelomonocytic leukemia: natural history and prognostic determinants.Mayo Clin Proc. 1989; 64: 1246-1254Abstract Full Text Full Text PDF PubMed Scopus (71) Google Scholar This disease is striking in its ability to express marked peripheral leukocytosis and hepatosplenomegaly. Unlike the acute monocytic leukemias, infiltration of soft tissues like gingiva, skin, cartilage, and the central nervous system is rare.2Tefferi A Hoagland HC Therneau TM Pierre RV Chronic myelomonocytic leukemia: natural history and prognostic determinants.Mayo Clin Proc. 1989; 64: 1246-1254Abstract Full Text Full Text PDF PubMed Scopus (71) Google Scholar, 3Shaw MT Monocytic leukemias: progress in human pathology. 1980; 11: 215-227Crossref PubMed Scopus (27) Google Scholar Cases of serous effusions have been well documented in myeloproliferative syndromes4Bubbley G Come P MacDougall D Thurner R Goldberg J Pericardial tamponade associated with myeloid metaplasia.Am J Hematol. 1983; 14: 185-188Crossref PubMed Scopus (11) Google Scholar, 5Haedershal C Hasselbalch H Devantier A Sauaniaki K Pericardial hematopoiesis with tamponade in myelofibrosis.Scand J Haematol. 1985; 34: 270-273Crossref PubMed Scopus (11) Google Scholar, 6Vilaseca J Arnau JM Tallada N Bernado L Lopez-Vivancos J Guardia J Agnogenic myeloid metaplasia presenting as massive pericardial effusion due to extramedullary hematopoiesis.Acta Haematol. 1985; 73: 239-240Crossref PubMed Scopus (11) Google Scholar, 7Pipoly GM Rogers J Cardiac tamponade resulting from pericardial extramedullary hematopoiesis.Cancer. 1979; 44: 1504-1506Crossref PubMed Scopus (13) Google Scholar, 8Shih LY Lin FC Kuo TT Cutaneous and pericardial extramedullary hematopoiesis with cardiac tamponade in chronic myeloid leukemia.Am J Clin Pathol. 1988; 89: 693-697Crossref PubMed Scopus (28) Google Scholar and acute monocytic leukemias;9Mufti GJ Oscier DG Hamblin TJ Nightingale A Parlow S Serous effusions in monocytic leukaemias.Br J Haematol. 1984; 58: 547-552Crossref PubMed Scopus (29) Google Scholar however, there are only eight case reports in the literature documenting pleuropericardial extramedullary hematopoiesis in CMML.9Mufti GJ Oscier DG Hamblin TJ Nightingale A Parlow S Serous effusions in monocytic leukaemias.Br J Haematol. 1984; 58: 547-552Crossref PubMed Scopus (29) Google Scholar, 10Manoharan A Malignant pleural effusion in chronic myelomonocytic leukemia.Thorax. 1991; 46: 461-462Crossref PubMed Scopus (13) Google Scholar, 11Oscier DG Worsely A Hamblin TJ Mufti GJ Treatment of chronic myelomonocytic leukemia with low dose etoposide.Br J Haematol. 1989; 72: 468-471Crossref PubMed Scopus (30) Google Scholar, 12Bonnet J Reiffers J Bernard P Bronstet A Aspects evolutifs des leucemies myelomonocytaires chroniques.Semin Hop Paris. 1981; 57: 327-331PubMed Google Scholar To date, we are unaware of documented case series describing the development of overt pericardial tamponade in the spectrum of myelodysplastic syndromes. In reviewing the literature of patients with leukemia who present with or develop pericardial effusion during the course of their disease, several interesting features are seen. (1) Almost all cases of tamponade are seen in patients with acute leukemia and in most of these cases of leukemic pericarditis, there is little evidence of cardiac dysfunction.13Roberts WC Bodey GP Wentlak PT The heart in acute leukemia: a study of 420 autopsy cases.Am J Cardiol. 1985; 21: 388-396Abstract Full Text PDF Scopus (141) Google Scholar (2) In almost all cases of acute leukemia presenting with pericardial tamponade, there is evidence for some degree of inflammatory pericarditis.14Jaffe N Traggis DG Tefft M Acute leukemia presenting with pericardial tamponade.Pediatrics. 1970; 45: 461-465Crossref PubMed Google Scholar In the myeloproliferative syndromes (AMM, CML), only five cases have documented pericardial extramedullary hematopoiesis with symptomatic effusions.4Bubbley G Come P MacDougall D Thurner R Goldberg J Pericardial tamponade associated with myeloid metaplasia.Am J Hematol. 1983; 14: 185-188Crossref PubMed Scopus (11) Google Scholar, 5Haedershal C Hasselbalch H Devantier A Sauaniaki K Pericardial hematopoiesis with tamponade in myelofibrosis.Scand J Haematol. 1985; 34: 270-273Crossref PubMed Scopus (11) Google Scholar, 6Vilaseca J Arnau JM Tallada N Bernado L Lopez-Vivancos J Guardia J Agnogenic myeloid metaplasia presenting as massive pericardial effusion due to extramedullary hematopoiesis.Acta Haematol. 1985; 73: 239-240Crossref PubMed Scopus (11) Google Scholar, 7Pipoly GM Rogers J Cardiac tamponade resulting from pericardial extramedullary hematopoiesis.Cancer. 1979; 44: 1504-1506Crossref PubMed Scopus (13) Google Scholar, 8Shih LY Lin FC Kuo TT Cutaneous and pericardial extramedullary hematopoiesis with cardiac tamponade in chronic myeloid leukemia.Am J Clin Pathol. 1988; 89: 693-697Crossref PubMed Scopus (28) Google Scholar Pericardial leukemic infiltration and/or tamponade have been described in patients with CML; however, this is distinctly rare.15Bierman HR Perkins EK Ortega P Pericarditis in patients with leukemia.Am Heart J. 1952; 43: 413-422Crossref PubMed Scopus (20) Google Scholar, 16Kaetz HW Selsky LM X-ray therapy in the treatment of cardiac tamponade in chronic myelocytic leukemia: report of a case.Conn Med. 1968; 32: 523-524PubMed Google Scholar, 17DiMatteo J Vacheron A Chanvin JP Subacute myeloid leukemia complicated by hemopericardium with tamponade.Arch Des Mai Dn Coeur Et Der Vaisseaux. 1969; 62: 1338-1348PubMed Google Scholar It is of interest that all the cases reviewed by Roberts et al13Roberts WC Bodey GP Wentlak PT The heart in acute leukemia: a study of 420 autopsy cases.Am J Cardiol. 1985; 21: 388-396Abstract Full Text PDF Scopus (141) Google Scholar had other evidence of extramedullary hematopoiesis aside from pericarditis. The presence of myelofibrosis and postsplenectomy extramedullary hematopoiesis may give some credence to the development of hematopoiesis in the pericardium in some of these patients. Extra-medullary hematopoiesis has been rarely documented in a subgroup of patients with CMML who have all expressed high peripheral monocyte counts with rapid clinical deterioration.9Mufti GJ Oscier DG Hamblin TJ Nightingale A Parlow S Serous effusions in monocytic leukaemias.Br J Haematol. 1984; 58: 547-552Crossref PubMed Scopus (29) Google Scholar, 18Duguid JKM Mackie MJ McVerry BA Skin infiltration associated with chronic myelomonocytic leukemia.Br J Haematol. 1983; 53: 257-264Crossref PubMed Scopus (55) Google Scholar, 19Copplestone JA Oscier DG Mufti GJ Hamblin TJ Monocytic skin infiltration in chronic myelomonocytic leukemia.Clin Lab Hematol. 1986; 8: 115-119Crossref PubMed Scopus (26) Google Scholar The most common site was skin and gingiva.9Mufti GJ Oscier DG Hamblin TJ Nightingale A Parlow S Serous effusions in monocytic leukaemias.Br J Haematol. 1984; 58: 547-552Crossref PubMed Scopus (29) Google Scholar, 18Duguid JKM Mackie MJ McVerry BA Skin infiltration associated with chronic myelomonocytic leukemia.Br J Haematol. 1983; 53: 257-264Crossref PubMed Scopus (55) Google Scholar, 19Copplestone JA Oscier DG Mufti GJ Hamblin TJ Monocytic skin infiltration in chronic myelomonocytic leukemia.Clin Lab Hematol. 1986; 8: 115-119Crossref PubMed Scopus (26) Google Scholar In all these cases, there was no evidence of secondary myelofibrosis and no patient had undergone splenectomy or splenic irradiation. Coexistent serous effusions—mainly pleuropericardial—have been documented in five cases of CMLL so far.9Mufti GJ Oscier DG Hamblin TJ Nightingale A Parlow S Serous effusions in monocytic leukaemias.Br J Haematol. 1984; 58: 547-552Crossref PubMed Scopus (29) Google Scholar, 10Manoharan A Malignant pleural effusion in chronic myelomonocytic leukemia.Thorax. 1991; 46: 461-462Crossref PubMed Scopus (13) Google Scholar, 11Oscier DG Worsely A Hamblin TJ Mufti GJ Treatment of chronic myelomonocytic leukemia with low dose etoposide.Br J Haematol. 1989; 72: 468-471Crossref PubMed Scopus (30) Google Scholar In one report, pericardial tamponade was the presenting manifestation of a patient with subacute myelomonocytic leukemia (SAMML) who was treated symptomatically with a pericardial window and then with chemotherapy resulting in a complete remission without recurrence of pericardial effusion. This patient eventually died of leukemic relapse refractory to chemotherapy 24 months after the diagnosis of SAMML.9Mufti GJ Oscier DG Hamblin TJ Nightingale A Parlow S Serous effusions in monocytic leukaemias.Br J Haematol. 1984; 58: 547-552Crossref PubMed Scopus (29) Google Scholar It is probable that this disease actually represents an accelerated phase of CMML. In the remaining seven cases of serous pleuropericardial effusions, chemotherapy with either low-dose etoposide9Mufti GJ Oscier DG Hamblin TJ Nightingale A Parlow S Serous effusions in monocytic leukaemias.Br J Haematol. 1984; 58: 547-552Crossref PubMed Scopus (29) Google Scholar, 10Manoharan A Malignant pleural effusion in chronic myelomonocytic leukemia.Thorax. 1991; 46: 461-462Crossref PubMed Scopus (13) Google Scholar, 11Oscier DG Worsely A Hamblin TJ Mufti GJ Treatment of chronic myelomonocytic leukemia with low dose etoposide.Br J Haematol. 1989; 72: 468-471Crossref PubMed Scopus (30) Google Scholar or low-dose cytarabine, 6-thioguanine, and etoposide10Manoharan A Malignant pleural effusion in chronic myelomonocytic leukemia.Thorax. 1991; 46: 461-462Crossref PubMed Scopus (13) Google Scholar seemed to resolve or prevent recurrence of these effusions. Three patients had coexistent extramedullary disease (gingiva and/or skin) that also resolved with chemotherapy.9Mufti GJ Oscier DG Hamblin TJ Nightingale A Parlow S Serous effusions in monocytic leukaemias.Br J Haematol. 1984; 58: 547-552Crossref PubMed Scopus (29) Google Scholar, 10Manoharan A Malignant pleural effusion in chronic myelomonocytic leukemia.Thorax. 1991; 46: 461-462Crossref PubMed Scopus (13) Google Scholar, 11Oscier DG Worsely A Hamblin TJ Mufti GJ Treatment of chronic myelomonocytic leukemia with low dose etoposide.Br J Haematol. 1989; 72: 468-471Crossref PubMed Scopus (30) Google Scholar Additionally, all these patients had WBC counts over 45 to 50×109/L and were found to have evidence of accelerating disease by the appearance of extramedullary features or increasing blast cell counts.9Mufti GJ Oscier DG Hamblin TJ Nightingale A Parlow S Serous effusions in monocytic leukaemias.Br J Haematol. 1984; 58: 547-552Crossref PubMed Scopus (29) Google Scholar, 10Manoharan A Malignant pleural effusion in chronic myelomonocytic leukemia.Thorax. 1991; 46: 461-462Crossref PubMed Scopus (13) Google Scholar, 11Oscier DG Worsely A Hamblin TJ Mufti GJ Treatment of chronic myelomonocytic leukemia with low dose etoposide.Br J Haematol. 1989; 72: 468-471Crossref PubMed Scopus (30) Google Scholar The treatment of such patients has been traditionally no different than that of other chemotherapy-sensitive hematopoietic malignancies—in that pericardiocentesis preceded chemotherapy. Because of the relative rarity of this condition, it is difficult to recommend the most optimum strategy of management. In a recertt paper, Buzaid et al20Buzaid AC Garewal HS Greenberg BR Managing malignant pericardial effusion.West J Med. 1989; 150: 174-179PubMed Google Scholar suggest that all patients with chemotherapy-sensitive tumors should receive systemic chemotherapy. Given that all our patients were initially unstable, pericardiocentesis was not unreasonable; however, it was also evident that in three of four patients presented herein, rapid control of the peripheral leukocytosis essentially prevented the recurrence of pericardial effusion. It is conceivable that this may have been coincidental; however, given the relative rarity of CMML and the further rare occurrence of tamponade in patients with CMML, the absence of recurrent effusion is probably secondary to controlled leukocytosis rather than a chance effect. Hence, this experience may suggest that chemotherapy may be instituted in conjunction with pericardiocentesis in an unstable patient. In a stable patient, it may be possible to proceed with chemotherapy alone. In conclusion, three important points are illustrated in this exercise: (1) pericardial tamponade in CMML is an uncommon complication but one that does respond to aggressive chemotherapy; (2) the malignant effusion leading to tamponade is often seen in situations of uncontrolled leukocytosis; and (3) although prior reports of pleuropericardial effusion in CMML have been accompanied by evidence of focus of disease elsewhere (ie, gingiva, skin), none of our cases demonstrated this. In effect, it is possible to have clinically significant pleuropericardial effusion without evidence of other sites of extramedullary hematopoiesis.