Flow Cytometry Analysis Versus E-Cadherin Immunohistochemistry for the Diagnosis of Pure Erythroid Leukemia: A Case Report.

Pure erythroid leukemia (PEL) is a rare form of acute myeloid leukemia characterized by the neoplastic proliferation of erythroblasts. PEL is associated with inferior survival outcomes, particularly among patients harboring complex karyotype abnormalities. In this case, we present a 21-year-old Sudanese man who presented to our ER with a two-week history of fever, shortness of breath, fatigue, and exercise intolerance. He had no significant personal medical history or family history of malignancy. A bone marrow biopsy revealed hypercellularity and infiltration by cells with an immature appearance. A flow cytometry (FC) analysis of the bone marrow aspirate revealed that approximately 21% of the total nucleated cells were negative for CD45 and positive for CD71, glycophorin A, and CD36 but negative for myeloperoxidase (MPO), CD33, CD13, CD61, CD41, and other lymphoid and myeloid markers. Consistent with the microscopic analysis, <1% of the total cells were identified as CD34/CD13/CD117-positive myeloblasts. Notably, all stains (CD45, MPO, CD34, CD163, CD61, glycophorin A) were negative except E-cadherin, which positively stained >80% of the cells. Our findings suggested a differential diagnosis that included erythroid leukemia and myelodysplastic syndrome (MDS). The morphological, FC, immunohistochemistry, and cytogenetic findings strongly supported a diagnosis of PEL.