Abnormal eosinophilia mimicking AML-M4Eo

开心100mm05xkw 2019-04-04

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Author: Xia Hou¹

Editor：Gailing Yuan²

Chief Editor：Xueyan Chen³

Reviewer：Jianfeng Zhu⁴

¹Department of Clinical Laboratory, The Second People's Hospital of Yunnan, Yunnan Province,China

²Department of Clinical Laboratory, The Fifth Division Hospital of Xinjiang Production and Construction Corps. Xinjiang Uygur Autonomous Region, China

³Department of Clinical Laboratory, The People's Hospital of Longhua District, Shenzhen, Guangdong Province, China

⁴Department of Clinical Laboratory, Zhongshan Hospital Fudan University, Shanghai, China

Figure 1. Peripheral blood smear showed blasts with prominent nucleoli (Wright stain, original magnification ×1000).

Figure 2. Peripheral blood smear showed neutrophil with dysplastic changes (Wright stain, original magnification ×1000).

Figure 3. Bone marrow aspirate smear displayed abnormal eosinophilia (Wright stain, original magnification ×1000).

Figure 4. Bone marrow aspirate smear showed blast cells with homogeneous pink colored cytoplasm (Wright stain, original magnification ×1000).

Figure 5. Myeloperoxidase was positive in some blast cells. (BM, original magnification ×1000）

Figure 6. Cytochemical features of AML. (upper left: CE stain; upper right: PAS stain; bottom left: NAE stain; bottom right: NAF stain. original magnification ×1000).

Figure 7. Flow cytometry immunophenotype of bone marrow revealed blast cells were positive for MPO, CD117, CD34, HLA-DR, CD38, CD33 and CD13.

A 42-year-old male admitted to hospital with dizziness, fatigue, abdominal pain for 3 days. Physical examination was normal. Laboratory findings showed white blood cell count 8.71×10⁹/L, red blood cell count 1.99×10¹²/L, hemoglobin 75 g/L and platelet 19×10⁹/L. Peripheral blood smear revealed 15% blasts without eosinophilia (Fig. 1) and neutrophil with dysplastic changes (Fig. 2). Bone marrow aspirate demonstrated marked hypercellularity with eosinophilic and granulocytic proliferation, and blast count (59.5%) with Auer rods (Fig. 3,4). The leukemic cells were positive for MPO (Fig. 5), naphthol AS-D chloroacetate esterase (CAE), Periodic acid-schiff (PAS) and α-naphthol acetate esterase (NAE+NAF) (Fig. 6). Immunophenotype of bone marrow revealed blasts were positive for CD34, MPO, CD117, CD34, HLA-DR, CD38, CD33 and CD13 (partial) (Fig. 7). The cytogenetic analysis identified a t (8; 21) (q22; q22) [20] karytype, and presence of a RUNX1-RUNX1T1 fusion transcript confirmed by molecular study. The final diagnosis was acute myeloid leukemia(AML) with t (8; 21) (q22; q22.1); RUNX1―RUNX1T1.

Multiple recurrent chromosomal aberrations had been identified in AML and used as one of the most important diagnostic and prognostic markers^[1]. The morphological changes of AML with t(8; 21) (q22; q22.1); RUNX1-RUNX1T1 showed predominantly neutrophilic maturation. This type of AML was associated with a high rate of complete remission and favorable long-term outcome. AML with t(8;21) (q22; q22) usually correlated with distinct morphological features including large size blasts with Auer rods, numerous azurophilic granules and large pseudo Chediak-Higashi granules as well as homogeneous pink colored cytoplasm^[3]. Bone marrow showed eosinophil precursors frequently increased without cytological or cytochemical abnormalities features of AML with inv (16) (p13.1q22) or t (16;16) (p13.1; q22)^[3], in which abnormal eosinophilic granulation or nuclear lobation was always suggestive of a clonal eosinophilic abnormality or neoplastic process. In present case, the abnormal granules resembled basophilic granules, but lacked myeloperoxidase and toluidine blue reactivity^[5]. These so called harlequin cells were associated with clonal myeloid disorders, typically a specific type of AML^[5]. An accurate diagnosis of AML should integrate with physical examination, morphology, immunophenotype, molecular biology, as well as cytogenetics.

References

[1] Ferrara F, Palmieri S, Leoni F. Clinically useful prognostic factors in acute myeloid leukemia. Crit Rev Oncol Hematol,2008, 66 (3): 181-193.

[2] Mathew S, Shurtleff S, Ribeiro RC, et al.A complex variant t(8;21) involving chromosome 3 in a child with acute myeloblastic leukemia with eosinophilia (AML M4Eo). Leuk Lymphoma, 2003, 44(1):183-187.

[3] Swerdlow SH, Campo E, Harris NL, et al. (Eds): WHO Classification of Tumours of Haematopoietic and Lymphoid Tissues (Revised 4th edition). IARC: Lyon 2017.

[4] Metzeler KH, Bloomfield CD. Clinical relevance of RUNX1 and CBFB alterations in acute myeloid leukemia and other hematological disorders. Adv Exp Med Biol, 2017,962:175-199.

[5] Larsen RL, Savage NM. Savage. How I investigate eosinophilia. Int J Lab Hematol, 2018 Nov 30. doi: 10.1111/ijlh.12955. [Epub ahead of print]

（Executive editor：Hui Zhang，Department of Clinical Laboratory,Henan Honliv Hospital, Henan Province, China）

异常嗜酸性粒细胞增多的AML

作者：侯霞云南省第二人民医院检验科

编辑：袁改玲第五师医院检验科

主编：陈雪艳深圳龙华区人民医院检验科

审稿专家：朱建锋复旦大学附属中山医院检验科

病史摘要：

男，42岁，因“头昏、乏力3天，腹痛伴发热1天”急诊就诊，T：40.2℃。血常规：血常规：WBC:8.71×10⁹/L，RBC 1.99×10⁹/L，PLT 19×10⁹/L，Hb 75g/L。退热治疗后患者自觉腹痛稍有缓解，全身浅表淋巴结未及肿大。血液科以“全血细胞减少查因”收住院。全身浅表淋巴结未及肿大。

初步诊断:1.全血细胞减少查因；2.发热查因；3.急性胰腺炎待排。

相关实验室检查：

血常规：

生化结果：

外周血涂片：

骨髓涂片：

精彩讨论：

侯霞-云南省第二人民院：各位老师看看这个病例考虑诊断什么？

李婷-丽水市人民医院：M4Eo。

黄秀群-昭通市一院：有异常嗜酸颗粒。

杨礼-汕头市中心医院：不排除MDS转化来的。

窦心灵-酒泉市人民医院：M2b伴异常嗜酸性粒细胞增多。

陈宏伟-秦皇岛市第一医院：同意窦老师的意见。

侯霞-云南省第二人民院：

细胞化学染色如下：

骨髓形态学报告：

流式细胞学检查：

染色体检查：

融合基因：

骨髓活检：

窦心灵-酒泉市人民医院：NaF抑制不明显。

陈宏伟-秦皇岛市第一医院：CD19和CD56没表达。

侯霞-云南省第二人民院：我一直对这个异常嗜酸性粒细胞纠结，双嗜性到底怎么理解？

陈宏伟-秦皇岛市第一医院：我觉得幼稚嗜酸有时候由于颗粒发育问题也有那种偏紫红色的颗粒浮在橘黄色颗粒上面，看上去像异常嗜酸性粒细胞，但那些颗粒的边界应该没有异常嗜酸的分界那么清楚。本身M2b的特征之一就是多伴有幼稚嗜酸细胞增多。

陈宏伟-秦皇岛市第一医院：外周血有假P-H畸形。但我奇怪流式怎么CD19,56都阴性呢？一般来说M2b的CD56常出现阳性，CD19也出现部分阳性。看来流式这种特征也不是百分之百可以出现。

最终诊断：急性髓系白血病伴t(8;21)(q22;q22)(RUNX1-RUNX1T1)

病例聚焦：

一、诊断标准

此类AML为伴有重现性遗传学异常AML，约占所有AML的30%。患者常为原发病例，本病具有与其特定细胞遗传学异常相对应的独特的形态学和免疫表型。这类患者临床表现独特，年轻患者居多，易合并发生髓系肉瘤。

二、诊断要点

1、形态学特点：

骨髓细胞形态学特征比外周血更加特异；原粒细胞较大，胞浆丰富嗜碱性明显，可见胞质空晕，多数有嗜天青颗粒和假性Chediak-Higashi颗粒。Auer小体常见，早幼、中幼和成熟中性粒细胞可有不同程度的病态造血，胞质呈均匀的粉红色；红系和巨核细胞发育正常；幼稚嗜酸性粒细胞常增多，但它们与AML伴inv（16）（p13.1q22）或t（16；16）（p13.1；q22）（CBFB-MYH11）的异常嗜酸性粒细胞的细胞形态和细胞化学特点不同。

2、免疫表型：

部分原始细胞强表达CD34、HLA-DR、MPO和CD13。但CD33常弱表达。在部分细胞中可见粒系成熟的标志CD15和（或）CD 65。部分原始细胞可同时表达CD34和CD15。经常表达淋系标志CD19、CD56和PAX5，也可表达胞内CD79a。有些病例表达TDT，表达CD56者可能预后较差。典型流式图如下：

3、染色体及分子生物学检查：

可见t(8;21)(q22;q22)平衡易位及RUNX1-RUNX1T1（AML1/ETO）融合基因。

小结：

许多与急性白血病诊断和预后与相应遗传学异常相关。AML伴t(8;21)(q22;q22)；RUNX1-RUNX1T1通常是一种中性粒细胞有成熟迹象的AML。以化疗后缓解率高和获得长期生存为特点。 t (8;21)(q22;q22)常表现为特征性的形态学特点：核质发育不平衡、“核幼浆老”，胞质染色异常、呈“朝阳红”或“黄沙样”改变，核分叶不良，胞质中可见空泡、包涵体。另外该病常伴有嗜酸性粒细胞比例增高。但是增高的嗜酸性粒细胞没有AML伴inv（16）（p13.1q22）或t（16；16）（p13.1；q22）；CBFB-MYH11的异常嗜酸性粒细胞的细胞学和细胞化学的特点。该患者虽然骨髓涂片中嗜酸性粒细胞比例高达15%（ANC），但形态无异常。异常嗜酸性粒细胞的颗粒常常大于正常幼稚嗜酸性粒细胞，紫色，有些时候由于颗粒过于密集模糊了细胞核的形态。