75 year old man presented with worsening cytopenia. Admission bloods showed haemoglobin 69 g/L, platelets 33 x 10⁹/L, neutrophils 2.5 x 10⁹/L and rare circulating blasts. Bone marrow aspirate showed population of blasts (63%) morphologically resembling proerythroblasts. However, occassional cytoplasmic blebs raised suspicion for megakaryoblasts. 

Flow cytometry showed two blast populations with similar size and CD117 positivity. One population was CD45 positive with CD34, CD13, C33, CD61 and CD41a expression. Negative glycophorin A and MPO. Second population was negative for CD45, CD34 and HLA-DR. CD71 and glycophorin A positive. Other megakaryocytic markers negative. 

Trephine biopsy was markedly hypercellular with diffuse infiltration of mononuclear cells which are ECAD and CD71 positive. Megakaryoblastic population not identified on IHC represented by CD41. 

Cytogenetics showed complex karyocyte with -7, -17 and - 5. 

Overall findings favoured Acute Erythorid leukaemia (WHO 2022).