Systemic mastocytosis with associated hematological neoplasm (SM-AHN) poses diagnostic challenges because of the coexistence of atypical mast cell proliferation and hematological neoplasms. We assessed the presence of SM-AHN in patients with acute myeloid leukemia (AML) with RUNX1::RUNX1T1 from 2014 to 2020. Bone marrow (BM) samples were evaluated for mast cell aggregates using CD117 and CD25 immunohistochemical (IHC) staining. The KIT D816V variant burden at diagnosis and post induction was assessed using droplet digital PCR. Among 23 patients diagnosed as having AML with RUNX1::RUNX1T1, four (17.4%) were also diagnosed as having SM-AHN. No significant differences in clinical characteristics or overall survival (P=0.565) were observed between patients with or without SM-AHN, except for the presence of KIT variants (P=0.040). After induction therapy, IHC staining revealed the presence of mast cell aggregates in the BM, and the KIT D816V variant burden decreased with decreasing blast count and was similar in BM aspirates, smear slides, and sections. Concomitant SM-AHN was not infrequent in AML patients with RUNX1::RUNX1T1. This study showed the importance of CD117 and CD25 IHC staining after induction chemotherapy for SM-AHN screening, especially in patients with KIT variants.

中文翻译：

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用 RUNX1::RUNX1T1 免疫组织化学染色来识别急性髓系白血病中伴随的全身性肥大细胞增多症。

由于非典型肥大细胞增殖和血液肿瘤共存，系统性肥大细胞增多症伴相关血液肿瘤 (SM-AHN) 对诊断提出了挑战。我们评估了 2014 年至 2020 年RUNX1::RUNX1T1急性髓性白血病 (AML) 患者中 SM-AHN 的存在。使用 CD117 和 CD25 免疫组织化学 (IHC) 染色评估骨髓 (BM) 样本的肥大细胞聚集体。使用液滴数字 PCR 评估诊断和诱导后的KIT D816V 变异负荷。在被诊断为患有RUNX1::RUNX1T1的 AML 的 23 名患者中，4 名 (17.4%) 也被诊断为患有 SM-AHN。临床特征或总生存期无显着差异（P= 0.565）在有或没有 SM-AHN 的患者之间观察到，除了存在KIT变体（P = 0.040）。诱导治疗后，IHC 染色显示 BM 中存在肥大细胞聚集体，并且KIT D816V 变异负荷随着原始细胞计数的减少而降低，并且在 BM 吸出物、涂片和切片中相似。伴随 SM-AHN 在RUNX1::RUNX1T1的 AML 患者中并不罕见。本研究表明诱导化疗后 CD117 和 CD25 IHC 染色对 SM-AHN 筛查的重要性，尤其是在具有KIT变异的患者中。