Diagnostic spectrum of hypereosinophilia based on bone marrow pathology: 10 years' experience at a tertiary care hospital

• Published in: International journal of laboratory hematology 2023-06, Vol.45 (3), p.328-336
• Main Authors: Kim, Hyunji, Cho, Young‐Uk
• Format: Article
• Language: English
• Subjects: Bone Marrow; Bone Marrow Examination; chronic eosinophilic leukemia; Humans; hypereosinophilia; Hypereosinophilic Syndrome - etiology; Hypereosinophilic Syndrome - genetics; karyotype; Leukocyte Count; PDGFRA; Tertiary Care Centers
• ISSN: 1751-5521; 1751-553X
• DOI: 10.1111/ijlh.14025

Background Hypereosinophilia (HE) is defined as peripheral blood (PB) eosinophil count exceeding 1.5 × 109/L. As the causes of HE can be diverse, the work‐up of patients was complicated. In this study, we aimed to categorize the underlying diseases associated with HE and demonstrate minimum diagnostic approach. Methods Cases presenting with HE within 7 days of bone marrow (BM) examination conducted between 2008 and 2019 were selected. Cases were classified by the revised 2022 WHO and ICC classification. We also assessed morphologic features of unclassified persisting HE (>4 weeks) patients according to the morphologic criteria suggested a previous study by Wang et al. Results A total of 364 patients were included. The work‐up confirmed primary HE in 38.7%, secondary HE in 48.9%, HE patients with insufficient evaluation in 13.7%. When conducted a slide review of HE patients with sustained HE more than 4 weeks among HE patients with insufficient evaluation, the morphological features showed abnormal eosinophils in PB/BM (69.0%/81.0%), hypercellularity (26.2%), myelofibrosis (7.1%), increased M:E ratio (5.3%), and dysmegakaryopoiesis (4.8%). Of these patients, 14 patients who met all morphologic criteria were suspected of CEL. Conclusions This study demonstrates that HE is associated with variable conditions. BM morphological assessment based on a robust criterion can help to confirm a MN irrespective of the presence of clonal markers. The work‐up of patients in whom ruled out the common secondary causes of HE requires a systematic but sufficient approach including at a minimum BM karyotyping, PDGFRA testing, lymphocyte immunophenotyping and TCR gene rearrangement.