中文摘要：

目的评价骨髓增生异常综合征（MDS）WHO标准和MDS最低诊断标准对骨髓原始细胞比例不增高（〈0．050）的MDS患者的诊断分型。方法回顾性收集1988年至2005年诊断的骨髓原始细胞比例不增高的210例MDS患者[FAB分型为难治性贫血（RA）或RA伴有环状铁粒幼红细胞（RARS）]，重新分析细胞形态并采集相关实验室检查资料，用WHO标准和MDS最低诊断标准对这些患者进行诊断分型。结果按WHO分型标准进行诊断分型，其中RA5例，RARS7例，难治性血细胞减少伴有多系发育异常（RCMD）76例，RCMD和环状铁粒幼红细胞（RCMD—RS）9例，MDS不能分类（MDS—U）35例，5q-综合征3例，无法分型75例。WHO标准不能分型的患者中，16例骨髓二系或三系发育异常，而血细胞仅-系减少的患者随访半年后9例出现二系以上血细胞减少，可归为RCMD；对44例骨髓仅红系发育异常，血细胞二系减少或全血细胞减少无法进行分型患者，重新进行形态学分析，将那些尚未述及的细胞发育异常形态改变纳入判定该系细胞发育异常细胞计数范围后，27例患者粒系形态异常细胞≥0．100，可归入RCMD或RCMD—RS；15例三系均无细胞发育异常患者，采用MDS最低诊断标准诊断为MDS5例，高度疑似MDS（HS－MDS）5例，意义未定的特发性血细胞减少（ICUS）5例。结论MDS中只有很少一部分患者是真正意义上的RA；关于MDS的细胞发育异常形态学异常的范畴和量的界定值仍值得进一步探讨；MDS最低诊断标准是对WHO标准的很好的细化和补充。

英文摘要：

Objective To apply the WHO criteria and the minimal diagnostic criteria to the classfication of myelodysplastic syndromes （ MDS ） with low percentage （ 〈 0. 050 ） bone marrow （ BM ） blasts. Methods Two hundred and ten MDS patients with less than 0. 050 BM blasts diagnosed between 1988 and 2005 according to FAB criteria were retrospectively reclassified with WHO criteria（2001 ） and minimal diagnostic criteria. Results According to the WHO criteria, 5 patients were diagnosed as refractory anemia （RA）, 7 as refractory anemia with ringed sideroblasts（ RARS）, 76 as refractory cytopenia with multilineage dysplasia（RCMD） , 9 as RCMD-RS, 35 as MDS-unclassified（MDS-U） , 3 as 5q- symdromes, and the rest 75 patients could not be classified suitably. Among the latter 75 patients 16 BM smears showed dysplasia in more than 2 cell lineage but only unilineage cytopenia in peripheral blood （PB）. Nine of them were reclassified as RCMD after followed up for more than half a year. Forty-four BM smears showed erythroid dysplasia only, but bicytopenia or pancytopenia in PB. Twenty-seven of them were classified as RCMD after follow-up. Fif- teen BM smears not showed dysplasia in any myeloid lineage were reclassified as MDS（5 patients）, HS-MDS （5 patients） and idiopathic cytopenia of uncertain significance （ICUS） （5 patients） according to the MDS minimal diagnostic criteria. Conclusion According to WHO criteria （2001）, RA is the least diagnosis in MDS. The minimal diagnostic criteria for MDS classification of patients not fulfilled the standard criteria of MDS.