Medline ® Abstracts for References 112,113

A patient with a myelodysplastic syndrome (MDS) and reticulocytosis of>50% in the absence of a correspondingly increased erythrocyte turnover is reported. Evaluation of the kinetics of erythrocyte turnover revealed a decreased erythrocyte life span of 44 days. From these data a prolongation of the reticulocyte maturation time to>20 days can be concluded. The patient's erythrocytes lacked the increase of mean corpuscular volume and a significant increase of erythrocyte enzymes that would be expected in marked reticulocytosis. This finding suggests that the reticulocytes represented not newly formed red blood cells, but "pseudoreticulocytes", i.e., mature erythrocytes that retained their substantia reticulofilamentosa.

A patient with myelodysplastic syndrome (refractory anemia) with marked and persistent reticulocytosis is presented. A referring diagnosis of hemolytic disease had been made. However, the 51Cr red cell survival was normal (T1/2 24 days). Reticulocyte morphology, red cell creatine content, and in vitro reticulocyte survival studies have suggested that the reticulocytosis arose as a consequence of delayed maturation of the reticulocytes. Two patients with myelodysplastic syndrome and delayed reticulocyte maturation have previously been described; in both patients, however, red cell survival was also shortened. Anemia with reticulocytosis, mimicking hemolytic disease, may be an unusual presentation of myelodysplastic syndrome.