Myelodysplastic syndromes (MDS) are a heterogeneous group of diseases, with a variable probability of transformation into acute leukemia, which is, in the vast majority of cases, of myeloid lineage. Nevertheless, rare cases of acute lymphoblastic leukemia in patients with previously diagnosed MDS have been reported. We describe a series of 3 cases of MDS/CMML marked with evolution to acute lymphoblastic leukemia (ALL) and provide a comprehensive review of the 49 cases documented in the literature so far. These sporadic events have only been published as single-case reports or small series to date. Such atypical cases emphasize the possibility of major phenotypic switches arising at the leukemic stem cell (LSC) and/or early progenitor levels, as a consequence of epigenetic and genomic events driving these changes in the bone marrow niche.

骨髓增生异常综合症（MDS）是一类异质性疾病，具有转化为急性白血病的可能性，而急性白血病在大多数情况下是髓系。然而，已经报道了先前诊断为MDS的患者中罕见的急性淋巴细胞白血病病例。我们描述了一系列3例MDS / CMML并标记为急性淋巴细胞白血病（ALL）的演变，并提供了迄今为止文献中49例的全面综述。迄今为止，这些零星事件仅作为单例报告或小编发表。这些非典型病例强调了由于表观遗传学和基因组事件驱动骨髓生态位变化的结果，在白血病干细胞（LSC）和/或早期祖细胞水平上出现了主要的表型转换的可能性。