Pure (acute) erythroid leukemia: morphology, immunophenotype, cytogenetics, mutations, treatment details, and survival data among 41 Mayo Clinic cases.

Pure erythroid leukemia (PEL), also known as acute erythroid leukemia (AEL), is recognized as a distinct morphologic entity by both the 2016 and 2022 World Health Organization (WHO) classification system. By contrast, the 2022 International Consensus Classification (ICC) includes PEL under a broader category of "acute myeloid leukemia with mutated TP53". We identified 41 Mayo Clinic cases of PEL (mean age 66 years, range 27-86; 71% males) and provide a comprehensive account of bone marrow morphology, immunophenotype, cytogenetic and mutation profiles. PEL was primary in 14 cases, therapy-related in 14, secondary in 12, and undetermined in one. All cases expressed biallelic TP53 alterations, including TP53 deletion/single TP53 mutation (68%), two TP53 mutations (29%) or two TP53 deletions (3%); additional mutations were infrequent. Karyotype was complex in all cases and monosomal in 90%. Treatment details were available in 29 patients: hypomethylating agent (HMA) alone (n = 5), HMA + venetoclax (n = 12), intensive chemotherapy (n = 4), supportive care/other (n = 8); no responses or allogeneic stem cell transplants were documented, and all patients died at a median 1.8 months (range 0.2-9.3). The current study highlights a consistent and reproducible set of morphologic and genetic characteristics that identify PEL as a distinct AML variant whose dismal prognosis requires urgent attention.