Retinoic acid syndrome (RAS) is the clinical syndrome that occurs after treatment of acute promyelocytic leukemia with all-trans-retinoic acid (ATRA). The patients experience fever, dyspnea, hypotension, respiratory distress, edema and weight gain. Chest x-ray will show pulmonary infiltrates and pleuropericardial effusion. The onset of this syndrome is usually 5-21 days after ATRA treatment when white blood cell counts are rising more than 10,000/cu.mm. The authors have reported a case of RAS. The patient was a 29-year-old man who had been working in a battery manufacturing factory for 7 years. He presented with easily bruising for one month. The initial blood test showed hematocrit of 36.2%, white blood cells count of 3,200/cu.mm with 28% neutrophils, 20% lymphocytes, 2% eosinophils and 50% promyelocytes and platelet of 20,000/cu.mm. Peripheral blood smear revealed numerous fragmented red blood cells. Bone marrow examination showed hypercellularity with abnormal promyelocytes of 95% and bone marrow cytogenetics was translocation of chromosome 15 and 17 [t (15;17)(q22;q12)]. The diagnosis was acute promyelocytic leukemia and the patient was treated with ATRA 45 mg/m2/day per oral starting on day 1 and intravenous idarubicin 10 mg/m2 on day 4, 5 and 6. On day 13, he had a body temperature of 39 ÌC and a dry cough. The white blood cells were rising to 7,400/cu.mm with 16% neutrophils. On day 18, he had oliguria, high grade fever, hypotension, cough with chest pain and white blood cells rose to 21,300/cu.mm with 65% neutrophils and rising of blood urea nitrogen and creatinine. Chest x-ray showed enlarged cardiac shadow with pleural effusion. Echocardiogram revealed moderate amount of pericardial effusion. The diagnosis of RAS was made and ATRA was withdrawn. Intravenous dexamethasone 4 mg every 6 hours and hemodialysis was started. The patientûs symptoms improved dramatically and bone marrow examination was in complete remission. He was subsequently given cytarabine and idarubicin as consolidation. This patient had clinical manifestation consistent with RAS, which improved after prompt treatment.

Keywords: Acute promyelocytic leukemia, All-trans-retinoic acid, Retinoic acid syndrome