BACKGROUND Neoplasms derived from plasmacytoid dendritic cells (PDCs) are currently divided into two broad categories: mature PDC proliferations associated with myeloid neoplasms (MPDMN) and blastic plasmacytoid dendritic cell neoplasm (BPDCN); only BPDCN is recognized in the WHO 2016 classification of hematopoietic neoplasms. We present seven patients with high grade myeloid neoplasms (MNs), mostly acute leukemias, having a spectrum of PDC differentiation and not fitting with MPDMN or BPDCN. METHODS We analyzed seven MN cases having increased myeloblasts and prominent CD56-negative PDC proliferations comprising 5-26% of bone marrow or blood cellularity as measured by flow cytometry. The cases included five acute myeloid leukemia (three FAB M4 subtype, two unclassified), one mixed phenotype acute leukemia, and one case of unclassified MN. RESULTS Six cases demonstrated immunophenotypic evidence of PDC differentiation from leukemic blasts, based on variable expression of CD34, CD45, CD123, and CD304 by the leukemic cells. Four cases had circulating PDC populations in blood. None of the cases met clinical or pathologic criteria for BPDCN. Morphologic review was available for four acute leukemia cases and demonstrated either nodular or interstitial infiltrates of PDCs. All cases had an aggressive clinical course, and three cases had FLT3 ITD mutation. CONCLUSIONS These cases demonstrate that high grade MNs, in particular AML, can exhibit PDC differentiation, with or without monocytic differentiation, in a manner distinct from MPDMN or BPDCN. The existence of MNs with immature PDC proliferations suggests that there is a broader spectrum of PDC-associated neoplasms than currently recognized. © 2019 International Clinical Cytometry Society.

中文翻译：

---

流式细胞仪鉴定具有浆细胞样树突状细胞分化的骨髓瘤的成熟谱。

背景技术源自浆细胞样树突状细胞（PDC）的肿瘤目前分为两大类：与髓样肿瘤（MPDMN）相关的成熟PDC增殖和非变性浆细胞样树突状细胞肿瘤（BPDCN）；和与骨髓样浆样树突状细胞瘤相关的成熟PDC。在世卫组织2016年造血肿瘤分类中仅认可BPDCN。我们介绍了七例高级别骨髓瘤（MNs）患者，主要是急性白血病，具有PDC分化谱，不适合MPDMN或BPDCN。方法我们通过流式细胞仪分析了7例MN病例，这些病例中有成肌细胞增加和CD56阴性PDC明显增生，占骨髓或血液细胞密度的5-26％。病例包括5例急性骨髓性白血病（3例FAB M4亚型，2例未分类），1例混合表型急性白血病和1例未分类MN。结果6例患者根据白血病细胞CD34，CD45，CD123和CD304的可变表达，证明了从白血病母细胞分化出PDC的免疫表型证据。4例血液中有循环的PDC人群。没有一个病例符合BPDCN的临床或病理学标准。形态学检查可用于4例急性白血病病例，并显示PDC的结节性或间质性浸润。所有病例均具有侵略性的临床病程，其中三例具有FLT3 ITD突变。结论这些案例表明，高等级的MNs，特别是AML，可以以与MPDMN或BPDCN不同的方式表现出PDC分化，有或没有单核细胞分化。PDC增殖不成熟的MN的存在表明，与PDC相关的肿瘤存在比目前公认的更广谱。©2019国际临床细胞计量学会。