THE PROGNOSTIC IMPACT OF ERYTHROID DYSPLASIA IN APLASTIC ANEMIA AND MYELODYSPLASTIC NEOPLASMS WITH SINGLE-LINEAGE DYSPLASIA

Introduction: While genetic aberrations are becoming increasingly critical in disease classification, morphological abnormalities defined by a 10% threshold in each lineage continue to play a significant role as a diagnostic tool for myelodysplastic neoplasms (MDS). However, erythroid lineage dysplasia has been reported in some cases of aplastic anemia (AA), a phenomenon noted as common in the UK guidelines. Methods: We assessed the impact of erythroid dysplasia on the survival in AA patients enrolled in an ongoing prospective registry, central morphological review (blinded), and follow-up study of AA and MDS conducted by the Japanese National Research Group on Idiopathic Bone Marrow Failure Syndromes. Furthermore, we compared the prognosis of AA patients with erythroid dysplasia with that of patients diagnosed in the same study with MDS presenting with single-lineage erythroid dysplasia (“MDS-SLED”). According to this study's definition, the criteria for excluding MDS are stringent, considering both bone marrow cellularity and megakaryocyte counts. Therefore, AA is not diagnosed when a decrease is not observed in the megakaryocyte count. Results: The study included a total of 32 cases of AA with erythroid dysplasia, 56 cases of AA without dysplasia, and 47 cases of MDS-SLED. The overall survival or leukemia-free survival showed no significant difference between AA patients with and without erythroid dysplasia (both p=0.14). Nevertheless, distinct differences were seen between AA with erythroid dysplasia and those diagnosed with MDS-SLED (both p