A Patient with Acute Erythroid Leukaemia with Granular Leukaemic Cells Mimicking Megakaryoblast

Excerpt

A 57-years-old male patient presented to the hospital complaining of chest tightness, dyspnea, fatigue, and loss of appetite. Initial hematological results revealed a total leukocyte count of 2.42 × 10⁹/L, erythrocyte count of 1.26 × 10¹²/L, hemoglobin of 43 g/L, and platelets of 76 × 10⁹/L. Peripheral blood smear was not significant. Bone marrow examination revealed infiltration by 46% of granular leukemic cells with large size mimicking megakaryoblast. And these megakaryoblast-like leukemic cells had large round nuclei, immature chromatin, prominent nucleolus, and high nuclear-to-cytoplasmic ratios (Fig. 1A). Moreover, these blasts were also characterized by the cytoplasmic granules with pseudopodia and vacuoles (Fig. 1B). And myeloperoxidase was negative for these cells (Fig. 1C). Moreover, periodic-acid Schiff staining showed strongly positive with a granular pattern on these blasts (Fig. 1D). Then the megakaryocytic leukemia was highly suspected on this patient. However, further bone marrow immunophenotypes by flow cytometry were positive for CD36 (Fig. 1E), CD71 (Fig. 1F), CD105, HLA-DR, CD34 CD117, CD58, CD4, CD38 and CD33, and negative for GlyA, CD41a, CD42b, CD61, MPO, CD14, CD64, CD2, CD3, CD5, CD7, CD8, CD10, CD11b, CD13, CD15, CD16, CD19, CD20, CD22, CD56, CD123, cCD79a, TdT and cCD3 on blast cells, exclude lymphocyte or megakaryocyte phenotype. Moreover, positive E-Cadherin staining on the bone marrow further supports the erythroid lineage. Thus, these findings were consistent with acute erythroid leukemia (AEL) with morphological features resembling the megakaryoblast. Meanwhile, cytogenetics showed a normal male karyotype, but genomic sequencing analysis revealed pathogenic mutations on TP53, KMT2D, and SETD2. Finally, AEL was diagnosed in this patient. …