Study on Clinical and Laboratory Characteristics of Acute Erythroid Leukemia with EPOR Amplification

Objective: To enhance the understanding of acute erythroid leukemia (AEL) with erythropoietin receptor (EPOR) amplification and to improve its precise diagnosis and individualized treatment strategies.

Methods: A thorough analysis of the clinical and laboratory characteristics of two cases of de novo acute erythroid leukemia were performed and literatures were reviewed.

Results: Case 1: A 57-year-old male presented with dizziness and fatigue for one week. The proportion of erythroblasts in bone marrow aspirations was 3.2%, 40.5%, and 55% in three separate punctures, with proerythroblasts accounting for 18.4%, 23.5%, and 41% respectively. Bone marrow biopsy showed extremely hypercellular areas, with up to 80% erythroblasts in focal areas, predominantly proerythroblasts. Flow cytometry revealed that approximately 14.72% of cells were erythroblasts expressing CD36, CD117, CD33, and partially CD13. The granulocyte proportion was relatively normal. Chromosome analysis revealed a complex karyotype, and only a TP53 gene c.559+2T>G splice site mutation was detected using myeloid neoplasm-related gene mutation panel, with a VAF of 35.0%. FISH analysis showed no deletion of the TP53 gene. The diagnosis of acute erythroid leukemia was made, and the patient received two courses of decitabine plus arsenic trioxide and decitabine alone. However, bone marrow examination showed no remission, and the patient had a complex karyotype with clonal evolution, resulting in a survival of 3 months.

Case 2: An 80-year-old male presented with chest tightness, dyspnea, and fatigue for 10 days. Bone marrow aspiration showed hypercellular marrow, with 94% erythroblasts, including 35% proerythroblasts, 52% basophilic erythroblasts, 5.5% polychromatophilic erythroblasts, and 1.5% orthochromatic erythroblasts. Flow cytometry revealed that approximately 11.69% of nucleated cells were blast/early erythroid cells expressing CD33, CD117, CD36, CD71, and CD105. Chromosome analysis showed a complex karyotype. Myeloid neoplasm-related gene mutation panel showed TET2 mutation (+), TPMT mutation (+), and a TP53 p.K132E missense mutation with a VAF of 59.4%. Copy number variation (CNV) analysis revealed EPOR amplification and IKZF gene deletion. The patient survived for 7 days.

Conclusion: The proportion of erythroblasts in bone marrow smears of acute erythroid leukemia can be underestimated due to aspiration dilution, emphasizing the importance of bone marrow biopsy pathology combined with immunohistochemistry. Acute erythroid leukemia with EPOR amplification exhibits more significant erythroblast proliferation and a more aggressive clinical course.

No relevant conflicts of interest to declare.