Diagnostic Value of Flow Cytometry Standardized Using the European LeukemiaNet for Myelodysplastic Syndrome

Background: Myelodysplastic syndromes (MDS) and idiopathic cytopenia of undetermined significance (ICUS) are heterogeneous hematological disorders characterized by hematopoietic dysplasia and/or chromosomal aberrancy. Objectives: This study aimed to evaluate the diagnostic value of flow cytometry standardized using the European LeukemiaNet (ELN) for MDS and ICUS by analyzing samples obtained from patients with cytopenia based on morphological examination, cytogenetic analysis, and flow cytometry. Methods: We retrospectively analyzed bone marrow samples aspirated from 253 consecutive patients (median age: 66 years [range: 1–92]) to identify the cause of cytopenia. Results: Sixty patients presented with MDS, and 16 with ICUS. MDS subtypes were distributed as follows: MDS with single-lineage dysplasia (n = 10); MDS with multi-lineage dysplasia (n = 10); MDS with ringed sideroblasts (n = 4); MDS with excess blasts-1 (n = 9); MDS with excess blasts-2 (n = 13), MDS unclassified (n = 5); 5q-syndrome (n = 6); and MDS/myeloproliferative neoplasms (n = 3). Four representative ELN indexes were used. Two or more ELN MDS indexes were in the abnormal range in 35 MDS cases (58.3%) and 4 ICUS cases (25.0%). Conclusions: Morphological examination remains the standard for MDS diagnosis. Considering the low incidence of genetically proven ICUS (20.2–27.5%), the low sensitivity of ELN MDS indexes for ICUS is considered a valuable alternative.