# 上皮坏死（Epithelium - Necrosis）

- 器官 / 系统：肺 / 呼吸系统（lung / respiratory-system）
- NTP 数据编号：ntp-0096
- 规范 URL：https://www.labsmart.cn/ntp/lung-epithelium-necrosis.html
- 中文图谱总页锚点：https://www.labsmart.cn/ntp-atlas.html#lung-epithelium-necrosis
- 原始出处：https://ntp.niehs.nih.gov/atlas/nnl/respiratory-system/lung/Epithelium%E2%80%93Necrosis
- 授权：美国联邦政府作品，公有领域；引用请标注 NTP Nonneoplastic Lesion Atlas
- 适用说明：仅供科研使用，不用于临床诊断

## 一句话结论
坏死（Figure 1、Figure 2、Figure 3、Figure 4）与变性被认为是细胞损伤连续统一体的组成部分，其中坏死代表不可逆的细胞损伤，变性代表可逆的细胞损伤。

## 病变描述（中文）
坏死（Figure 1、Figure 2、Figure 3、Figure 4）与变性被认为是细胞损伤连续统一体的组成部分，其中坏死代表不可逆的细胞损伤，变性代表可逆的细胞损伤。坏死的 light microscopic 特征包括核固缩、核碎裂或核溶解、细胞肿胀、细胞细节丧失、细胞碎裂以及胞质嗜酸性增强（其中胞质常呈均质外观）。大面积坏死（Figure 2、Figure 3、Figure 4）还可能伴有组织结构破坏、大面积坏死碎屑、染色强度丧失以及炎性细胞。毒性损伤所致气道被覆上皮细胞坏死，常以坏死细胞或细胞碎屑脱落入管腔为特征。可逆性细胞损伤的 light microscopic 标志包括细胞肿胀、胞质空泡化、核周透明间隙、胞质泡形成、Clara 细胞正常顶端泡丧失以及纤毛丧失。在某些情况下，存活细胞从上皮表面脱落，以及上皮内散在细胞的核浓缩（固缩）和细胞皱缩，提示单个细胞即将死亡，可判读为上皮变性，因为其可能与上皮表面的可逆性损伤相一致，且可能缺乏明确的坏死证据。其他病变常伴随坏死和变性出现，如炎症和出血。坏死性病变的解剖位置可能因受试物的理化性质或特定细胞类型对受试物的易感性而有所不同。终末细支气管和肺泡管的上皮（即 centriacinar 区域）以及肺泡尤其易受损伤，原因在于表面积大、I 型肺泡细胞脆弱、Clara 细胞中 P450 酶的代谢活性以及黏液层通常较薄。

## 诊断与分级建议（NTP 共识，中文）
肺，上皮 - 坏死：只要存在即应诊断并分级。诊断中应包含部位修饰词，以指示病变在肺内的位置（例如 alveolus、bronchiole），因为毒性损伤可优先靶向特定部位。如果受累部位超过一个，可省略部位修饰词，并在病理学描述中描述各部位。变性与坏死在形态学上存在显著重叠，因此病理学家在诊断这些病变时需要运用其最佳判断。如果坏死继发于另一过程，例如严重炎症，则宜诊断主要过程并在描述中描述坏死。如果坏死与并发的相关病变（例如炎症）均显著，病理学家可选择记录两者并分别分级。同样，病理学家在决定是否单独诊断坏死或变性时需要运用其判断。如果坏死细胞已脱落，暴露出下方组织，则应使用术语“ulcer”或“erosion”（见 Lung - Ulceration）。然而，如果坏死细胞仍存在并覆盖基底膜，则坏死是首选诊断。相关链接：Lung - Ulceration

## 英文原文 · Comment
Necrosis ( Figure 1 , Figure 2 , Figure 3 , and Figure 4 ) and degeneration are considered to be parts of the continuum of cell damage, with necrosis representing irreversible cell damage and degeneration representing reversible cell damage. The light microscopic features of necrosis include nuclear pyknosis, karyorrhexis, or karyolysis, cell swelling, loss of cellular detail, cell fragmentation, and cytoplasmic hypereosinophilia (in which the cytoplasm often has a homogeneous appearance). Large areas of necrosis ( Figure 2 , Figure 3 , and Figure 4 ) may also have disrupted tissue architecture, large areas of necrotic debris, loss of staining intensity, and inflammatory cells. Necrosis of the epithelial cells lining the airways as a result of toxic injury is often characterized by sloughing of necrotic cells or cellular debris into the lumen. The light microscopic hallmarks of reversible cell damage include cellular swelling, cytoplasmic vacuolation, perinuclear clear spaces, formation of cytoplasmic blebs, loss of normal apical blebs from Clara cells, and loss of cilia. In some cases, detachment of viable cells from the epithelial surface and nuclear condensation (pyknosis) and cellular shrinkage of scattered cells within the epithelium, suggestive of imminent death of individual cells, may be interpreted as epithelial degeneration because it may be consistent with reversible damage to an epithelial surface, and evidence of outright necrosis may be lacking. Other lesions often accompany necrosis and degeneration, such as inflammation and hemorrhage. The anatomic location of necrotic lesions may vary due to the physicochemical properties of the test agent or the susceptibility of a particular cell type to the test agent. The epithelium of the terminal bronchioles and alveolar ducts (i.e., the centriacinar region) and alveoli are particularly susceptible to injury due to the large surface area and fragility of the alveolar type I cells, the metabolic activity of P450 enzymes in Clara cells, and the generally thinner mucous layer.

## 英文原文 · Recommendation
Lung, Epithelium - Necrosis should be diagnosed and graded whenever present. A site modifier should be included in the diagnosis to indicate the location of the lesion within the lung (e.g., alveolus, bronchiole) since toxic insults can preferentially target specific sites. If more than one site is affected, the site modifier may be omitted and the locations described in the pathology narrative. There is significant overlap, morphologically, between degeneration and necrosis, so the pathologist will need to use his or her best judgment when diagnosing these lesions. If the necrosis is secondary to another process, such as severe inflammation, it is preferable to diagnose the major process and to describe the necrosis in the narrative. If the necrosis and a concurrent, related lesion (e.g., inflammation) are both prominent, the pathologist may choose to record both lesions and grade them separately. Again, the pathologist will need to use his or her judgment in deciding whether or not to diagnose the necrosis or degeneration separately. If the necrotic cells have detached, exposing the underlying tissue, the term "ulcer" or "erosion" should be used (see Lung - Ulceration ). However, if the necrotic cells are still present and covering the basement membrane, necrosis is the preferred diagnosis. Related Links: Lung - Ulceration

## 配图
- https://www.labsmart.cn/ntp-atlas-images/ntp_0859.jpg
- https://www.labsmart.cn/ntp-atlas-images/ntp_0857.jpg

整理：北京天融慧通科技有限责任公司（LabSmart）｜ https://www.labsmart.cn