Diffuse alveolar hemorrhage in acute promyelocytic leukemia patients treated with ATRA - A manifestation of the basic disease or the treatment

All-trans-retinoic acid (ATRA) is considered the recommended induction treatment for acute promyelocytic leukemia. Ln the pre-ATRA era pulmonary bleeding was a common cause of death in these patients, mostly due to disseminated intravascular coagulation which was further exacerbated by the;administration of chemotherapy. Although ATRA syndrome, the most serious adverse effect of ATRA treatment, involves the lungs, pulmonary hemorrhage has only rarely been reported as a manifestation of ATRA syndrome. Here we describe 2 patients who developed diffuse alveolar hemorrhage during treatment with ATRA. The possible mechanisms of pulmonary bleeding in these cases are discussed.