has part has part characteristic of part of has modifier erythroid lineage cell Abnormal bone marrow cell morphology Abnormal erythroid lineage cell morphology Proerythroblasts are the earliest recognizable erythroid precursors. They are followined during the process of hematopoiesis by basophilic erythroblasts, polychromatic (polychromatophilic) erythroblasts, orthochromatic erythroblasts (normoblasts), reticulocytes, and finally mature erythrocytes (red blood cells). This term encompasses structural anomalies of erythroblast precursors in the bone marrow. morphology abnormal