Foamy cell syndrome associated with repeated platelet transfusions.

Variable numbers of foamy cells (macrophages with foamy cytoplasm) were noted in generalized organs from four patients who received repeated were noted in generalized organs from four patients who received repeated platelet transfusions. The underlying disease in three cases was aplastic anemia, and the remaining case was chronic myelocytic leukemia. In two patients (aplastic anemia and chronic myelocytic leukemia) bone marrow transplantation (BMT) was done. Opportunistic infection was noted in three out of four cases. The foamy cells were stained black with Sudan black B. Variable amounts of materials immunoreactive with antihuman platelet antibody were demonstrated in most of the foamy cells. Ultrastructurally, the foamy cells contained myelin-like materials. The foamy cells described here resembled those demonstrable in the spleen from patients with idiopathic thrombocytopenic purpura. We suggest that the foamy appearance of the macrophage results from incomplete intracellular degradation of phagocytosed platelets.