Hidden myelodysplastic syndrome (MDS): A prospective study to confirm or exclude MDS in patients with anemia of uncertain etiology

Diagnosis of myelodysplastic syndromes (MDSs) when anemia is the only abnormality can be complicated. The aim of our study was to investigate the primary causes of anemia and/or macrocytosis of uncertain etiology.We conducted a multicenter, prospective study over 4 months in three hematology laboratories. In step 1, we used an automated informatics system to screen 137 453 hemograms for cases of anemia and/or macrocytosis (n = 2702). In step 2, we excluded all patients whose anemia appeared to be due to a known cause. This left 290 patients had anemia of uncertain etiology. In step 3, we conducted further investigations, including a peripheral blood smear, and analysis of iron, vitamin B12, folate, and thyroid hormone levels.A differential diagnosis was obtained in 139 patients (48%). The primary causes of anemia were iron deficiency (n = 59) and megaloblastic anemia (n = 39). In total, 25 hematologic disorders were diagnosed, including 14 patients with MDS (56%). The median age of MDS patients was 80 years, 12 had anemia as an isolated cytopenia, and most (n = 10) had lower-risk disease (IPSS-R ≤ 3.5). SF3B1 mutations were most frequent (n = 6) and correlated with the presence of ring sideroblasts (100%) and associated with better prognosis (P = 0.001).Our prospective, four-step approach is an efficient and logical strategy to facilitate the diagnosis of MDS on the basis of unexplained anemia and/or macrocytosis, and may allow the early diagnosis of the most serious causes of anemia. Molecular analysis of genes related to MDS could be a promising diagnostic and prognostic approach.