Pleural Effusion as the Initial Manifestation of Chronic Myelomonocytic Leukemia

Chronic myelomonocytic leukemia (CMML) is a disease of the elderly, and by far the most frequent overlap myelodysplastic/ myeloproliferative neoplasm in adults. Aside from the chronic monocytosis in both peripheral blood and bone marrow that remains the cornerstone of its diagnosis, the clinical presentation of CMML includes dysplastic features, cytopenias, excess of blasts, or myeloproliferative features including high white blood cell count or splenomegaly. Prognosis is variable, with several prognostic scoring systems reported in recent years, and treatment is poorly defined. Pleural effusion in patients with CMML is a rare occurrence and poorly understood. We report a rare case of CMML patient presenting with pleural effusion as the first clinical sign.