Bronchoalveolar lavage of alveolar hemorrhage in the differentiation syndrome

Bronchoalveolar lavage from a patient with differentiation syndrome and alveolar hemorrhage. Image A shows an alveolar macrophage ringed by acute promyelocytic leukemia (APL) cells on a background of erythrocytes. Image B shows two alveolar macrophages ingesting erythrocytes on a background of erythrocytes and scattered APL cells. The presence of erythrocytes within the alveolar macrophages suggests alveolar hemorrhage rather than acute trauma at the time of bronchoscopy. The APL cells are present in the BAL due to the degree of hemorrhage.