[A "retinoic acid syndrome" observed in two cases of acute promyelocytic leukemia].

Two cases of acute promyelocytic leukemia (APL) treated with all-trans retinoic acid (ATRA) developed fever, dyspnea and chest pain. A chest roentgenogram showed bilateral pleural effusion (case 1) and bilateral interstitial infiltration (case 2). The first case was a 50-year-old female in her first relapse, who was initially diagnosed as having pleuritis tuberculosa and was treated with anti-tuberculotic agents. Her symptoms continued for 44 days and complete remission was achieved 53 days after commencing ATRA therapy. The second case was a previously untreated 46-year-old male. His case had been diagnosed as adult respiratory distress syndrome and he had been treated with prednisolone. His symptoms rapidly improved and complete remission was achieved 38 days after the ATRA therapy. This was the first report of patients in Japan considered to have developed "retinoic acid syndrome (RAS)". In our five APL cases treated with ATRA, the syndrome was not always accompanied by peripheral blood leukocytosis even though the two cases with RAS showed higher leukocyte counts than the other two cases without RAS and also had DIC. We should pay attention to the severe respiratory symptoms that develop in APL patients after ATRA treatment and immediate steroid therapy is required for such patients.