Leukemic Pleural Effusion in Acute Promyelocytic Leukemia: A Case Report

ABSTRACT

In patients with acute myeloid leukemia (AML), pleural effusion may be attributed to various factors, including infection, hypoalbuminemia, and renal failure. However, leukemic infiltration of the pleural fluid is rarely reported and poorly understood. Extramedullary diseases have been reported with increasing frequency as the survival rates of patients with AML have increased. However, the reported prognostic effects of leukemic pleural effusion in patients with AML range from none to a worse prognosis. Here, we report a case of acute promyelocytic leukemia (APL) in a patient exhibiting leukemic pleural effusion with fluorescence in situ hybridization (FISH) results indicating the presence of the PML-RARA fusion gene. A 52-year-old man presented with pancytopenia, dyspnea, and fever. He had a medical history of hypertension, end-stage renal disease, and hepatitis B virus-related liver cirrhosis. A peripheral blood smear revealed the presence of multiple abnormally hypergranular promyelocytes. White blood cell differential counts were not performed due to severe pancytopenia. A bone marrow examination, immunophenotyping analysis, and cytogenetic and molecular studies revealed APL. The patient was treated with all-trans retinoic acid immediately after abnormal promyelocytes were observed in the peripheral blood smear, but induction chemotherapy was delayed because of his poor condition. His persistent dyspnea and abdominal discomfort led to a thoracentesis and the observation of abnormal promyelocytes that were positive for PML-RARA fusion gene by FISH. To our knowledge, this is the first report of leukemic pleural infiltration with PML-RARA fusion gene-positivity via FISH.