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Multiomic Characterization of a Rare Case of Pediatric Acute Leukemia With a Novel ANGPT1::HOXA10-AS Fusion

Year: 2026

Type: article

Abstract: Patient CaseA 13-month-old previously healthy female was referred to hematology for isolated thrombocytopenia noted on routine CBC screening at her 1-year well-child visit.At the time, she was noted to have experienced progressive weight loss over a period of 2 months, falling from the 63rd to 17th percentile.She was closely monitored by hematology with serial CBCs over the next 6 months, demonstrating persistent isolated thrombocytopenia.Her follow-up CBC at age 19 months was subsequently notable for WBC 16,600/uL, hemoglobin 8.6 g/dL, platelets 13,000/ uL, and the presence of 17.4% blasts.Assessments of bone marrow aspirate smears and biopsy were performed (Fig 1A), demonstrating sheets of blasts with irregular nuclei, speckled chromatin, indistinct nucleoli, and scant cytoplasm, accounting for approximately 50% of cellularity.The aspirate smears demonstrated variably sized blasts with round to ovoid nuclei, fine dispersed chromatin, occasional 1-3 small nucleoli, and scant to moderate amounts of azurophilic cytoplasm, whereas the bone marrow trephine cores demonstrated sheets of medium-sized to large blasts with irregular to ovoid nuclei, speckled chromatin, indistinct nucleoli, and scant cytoplasm, accounting for approximately 50% of cellularity.Flow cytometric analyses of the peripheral blood and bone marrow aspirate demonstrated a blast population positive for CD58, CD33, CD4(dim), CD71, and HLA-DR.The blasts lacked expression of cCD3, CD7, CD19, CD13, CD117, MPO, CD15, and other B-cell and T-cell markers.Immunohistochemical staining of the bone marrow biopsy demonstrated CD33 and CD4 positivity of leukemia blasts, whereas GATA1, MPO, and CD117 were negative.CD42b highlighted a minor subset of blasts, found in small clusters, with a membranous and perinuclear dot-like Golgi pattern.Reticulin stain demonstrated grade 1 fibrosis.While the expression of CD41, CD42b, and CD61 was negative on the majority of cells, approximately 40% of cells demonstrated

Source: JCO Precision Oncology

DOI: 10.1200/po-26-00409