PSEUDORETICULOCYTOSIS IN A PATIENT WITH MYELODYSPLASIA

A patient with a myelodysplastic syndrome (MDS) and reticulocytosis of >50% in the absence of a correspondingly increased erythrocyte turnov er is reported. Evaluation of the kinetics of erythrocyte turnover rev ealed a decreased erythrocyte life span of 44 days. From these data a prolongation of the reticulocyte maturation time to >20 days can be co ncluded. The patient's erythrocytes lacked the increase of mean corpus cular volume and a significant increase of erythrocyte enzymes that wo uld 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 s ubstantia reticulofilamentosa.