AML with mutated TP53, therapy-related, with basophilic differentiation, partial CD22, and ring sideroblasts Free

A woman, aged 62 years, with a 7.5-year history of ovarian cancer and on chemotherapy, presented with anemia/circulating blasts. Peripheral blood examination showed a leukocyte count of 31.3 × 10⁹/L, neutrophil count of 3.8 ×10⁹/L, hemoglobin level of 7.9 g/dL, platelet count of 55 ×10⁹/L, and blast count of 55.6%, as well as increased basophils/basophilic myeloid precursors (panel A; Wright-Giemsa stain, 100× lens objective). Flow cytometry analysis of aspirate revealed 78% of blasts, which were CD34⁺/CD117⁺(variable)/HLA-DR⁺(variable)/CD13⁺/CD33⁺/CD38⁺/CD123⁺/cMPO(variable)/CD7⁺(aberrant) (panel B). A subset of blasts (6.64%) was CD22⁺ /CD11b⁺/CD13⁺/CD33⁺/CD123⁺(bright)/CD15^–/CD19^–/CD10^–/CD79^–/TdT^– (panel C). Marrow aspirate showed hypercellularity with increased blasts, some with basophilic granules, 15% basophilic myeloid precursors/basophils (panel D; May-Grünwald Giemsa stain, 100× lens objective), megakaryocytic/erythroid dysplasia, and 18% ring sideroblasts (RS) (panel D, inset; Perls stain, 100× lens objective). Optical genome mapping showed a highly complex karyotype (CK) including del(5q) and del(13q) (panel E). Next-generation sequencing showed biallelic TP53 (variant allele frequency: 49.6%; 42.5%) and PRPF40B/TET2 mutations. A diagnosis of acute myeloid leukemia (AML) with mutated TP53, therapy-related was rendered per International Consensus Classification criteria. The patient died 3 months later.

AML with basophilic differentiation is often associated with t(6;9)(p22.3;q34.1)/DEK::NUP214 and only rarely reported in AML with myelodysplasia-related cytogenetic abnormalities. CD22, a B-lineage marker, can be moderately expressed in basophils. Its positivity, along with CD123⁺(bright)/CD13⁺/ CD33⁺/CD11b⁺/CD15^–/basophilic granules, supports basophilic differentiation. RS in AML is associated with CK/TP53 mutations. AML with mutated TP53, therapy-related with basophilic differentiation, partial CD22/RS is rare, reflecting an aggressive disease with poor outcomes.

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