Balloon-like platelets in myelodysplastic syndromes—a feature of dysmegakaryopoiesis?

Abstract

Large bizarre platelets are a frequent finding in the peripheral blood of the myelodysplastic syndrome (MDS). In this study we describe a distinct subpopulation of platelets in MDS which by phase contrast microscopic examination seems to have a balloon-shaped bulge of the cell membrane. Increased numbers of these atypical platelets were found in 24 of 27 MDS patients (89%). Only 3 patients, all with ringsideroblastic anemia, had normal platelet morphology. The number of atypical platelets were negatively correlated ( r = 0.44; p = 0.021) to the peripheral platelet counts in MDS. Among 48 patients with acute leukemia, chronic lymphoproliferative or chronic myeloproliferative disorders, 13 (27%) had atypical platelets, Here, but not in the MDS group, atypical platelets seemed to be associated with recent chemotherapy. In a group of patients with benign hematological disorders abnormal platelet morphology was seen only occasionally. The described atypical platelets most likely reflect maturation disturbances of the megakaryopoiesis. An increased value (>1%) in a cytopenic patient would suggest a diagnosis of MDS, unless associated with recent cytotoxic therapy.