Castoldi G L, Liso V, Specchia G, Tomasi P
Institute of Hematology, University of Ferrara, Italy.
Leukemia. 1994;8 Suppl 2:S27-32.
Among AML with maturation, acute promyelocytic leukemia (APL) represents a distinct subtype which accounts for 5-10% of all the FAB variants. APL may be recognized by different cytological pictures: (i) Hypergranular APL, the most typical form, showing promyelocytes with cytoplasm packed with purple granules. Most of the primary granules may be incorporated into Auer rods, sometimes stacked in bundles of faggots. (ii) Microgranular APL, characterized by fine dust-like granulation in the cytoplasm; some promyelocytes may even appear agranular by light microscopy. Most of the cells show bilobed or folded nuclei, a picture which may simulate that of acute myelomonocytic leukemia. (iii) Hyperbasophilic form, characterized by cells with high N/C ratio, and strongly basophilic cytoplasm with either sparse or no granules. Conspicuous cytoplasmatic budding is usually present, recalling the feature of micromegakaryocytes. Strong positivity for myeloperoxidase, Sudan black B and chloroacetate esterase represents the typical cytochemical pattern of M3; usually a weaker reactivity may be observed in M3v. However, sometimes a degree of cytochemical heterogeneity of APL cells may be observed, as suggested by cases displaying a strong sodium fluoride-sensitive nonspecific esterase reaction. Recently a distinct entity associated with basophilic differentiation has been described. Differential diagnosis of this form with M2-baso subtype and with cases of MDS or AML with basophilia (M2, M4 with t(6;9) translocation) may be obtained by the use of cytochemistry, cytogenetic investigations, and electron microscopy.
在伴有成熟的急性髓系白血病（AML）中，急性早幼粒细胞白血病（APL）是一种独特的亚型，占所有FAB分型变异型的5%-10%。APL可通过不同的细胞学表现来识别：（i）颗粒增多的APL，最典型的形式，显示早幼粒细胞的胞质内充满紫色颗粒。大多数初级颗粒可融合形成Auer小体，有时呈束状排列。（ii）微颗粒型APL，其特征为胞质内有细小的尘样颗粒；部分早幼粒细胞在光镜下甚至可能看似无颗粒。大多数细胞显示双叶或折叠核，这种表现可能类似急性粒单核细胞白血病。（iii）嗜碱性增强型，其特征为细胞核质比高，胞质强烈嗜碱性，颗粒稀疏或无颗粒。通常可见明显的胞质芽生，类似微巨核细胞的特征。髓过氧化物酶、苏丹黑B和氯乙酸酯酶呈强阳性是M3的典型细胞化学模式；M3v通常反应较弱。然而，有时APL细胞可能会出现一定程度的细胞化学异质性，如一些病例显示对氟化钠敏感的非特异性酯酶反应较强。最近描述了一种与嗜碱性分化相关的独特实体。通过细胞化学、细胞遗传学研究和电子显微镜检查可对该型与M2-baso亚型以及骨髓增生异常综合征（MDS）或伴有嗜碱性粒细胞增多的AML（M2、t(6;9)易位的M4）病例进行鉴别诊断。
