髓外造血Extramedullary Hematopoiesis · 淋巴结 · 免疫系统 · NTP ntp-0015
诊断要点：淋巴结中的髓外造血应当诊断并分级。淋巴结中出现该病变时应促使评估其他器官是否存在EMH（尤其是脾和肝）。
病变描述
虽然骨髓是造血的主要部位，但淋巴结可能是髓外造血（extramedullary hematopoiesis，EMH）的部位。淋巴结中的EMH通常是对血液细胞急剧丢失或对额外血液细胞需求增加的生理性反应。诱发因素包括出血、感染、严重炎症、骨髓纤维化和肿瘤。EMH的特征是不同程度地混合存在髓系、红系和巨核系细胞，主要存在于淋巴结髓索内（Figure 1、Figure 2）。某一造血细胞谱系可能占优势，并可见不同程度的未成熟细胞。EMH应与炎性浸润和粒细胞性白血病相鉴别。淋巴结中的炎性浸润通常发育成熟，可为单一或混合细胞类型（见淋巴结-炎症）。粒细胞性白血病的特征是高数量的未成熟肿瘤性髓系细胞累及多个器官。髓外造血的既往术语包括“造血细胞增生”和“髓系增生”。
诊断与分级建议（NTP 共识）
淋巴结中的髓外造血应当诊断并分级。淋巴结中出现该病变时应促使评估其他器官是否存在EMH（尤其是脾和肝）。相关链接：肝-髓外造血 淋巴结-炎症 脾-髓外造血
图谱
英文原文
展开 NTP 官方英文描述与建议
Comment：
While the bone marrow is the major site of hematopoiesis, lymph nodes may be a site of extramedullary hematopoiesis (EMH). EMH in lymph nodes typically occurs as a physiologic response to a dramatic loss or increased need for additional blood cells. Examples of inciting factors include hemorrhage, infection, severe inflammation, myelofibrosis, and neoplasia. EMH is characterized by a mixture, to varying degrees, of myeloid, erythroid, and megakaryocytic cells and is primarily present within the lymph node medullary cords ( Figure 1 and Figure 2 ). One lineage of hematopoietic cell may predominate, and various degrees of immaturity may be seen. EMH should be distinguished from inflammatory infiltrates and granulocytic leukemia. Inflammatory infiltrates in the lymph node are generally mature in development and may be a single or mixed cell type (see Lymph Node - Inflammation ). Granulocytic leukemia is characterized by high numbers of immature neoplastic myeloid cells that involve multiple organs. Previous terms for extramedullary hematopoiesis include ''hematopoietic cell proliferation" and "myeloid hyperplasia."
Recommendation：
Extramedullary hematopoiesis in lymph nodes should be diagnosed and graded. The presence of this lesion in lymph nodes should prompt evaluation of other organs for EMH (especially the spleen and liver). Related Links: Liver - Extramedullary Hematopoiesis Lymph Node - Inflammation Spleen - Extramedullary Hematopoiesis
来源与引用
原始条目：https://ntp.niehs.nih.gov/atlas/nnl/immune-system/lymph-node/ExtramedullaryHematopoiesis
图谱总目录：NTP Nonneoplastic Lesion Atlas。 内容属美国联邦政府作品（公有领域），可引用；引用时请标注来源。
建议引用格式：NTP Nonneoplastic Lesion Atlas. Extramedullary Hematopoiesis (lymph-node). LabSmart 中文版：
https://www.labsmart.cn/ntp/lymph-node-extramedullary-hematopoiesis.html
中文图谱总页（可展开对照全部 595 条）：https://www.labsmart.cn/ntp-atlas.html#lymph-node-extramedullary-hematopoiesis