# 导管鳞状化生（Duct Metaplasia Squamous）

- 器官 / 系统：唾液腺 / 消化系统（salivary-gland / alimentary-system）
- NTP 数据编号：ntp-0237
- 规范 URL：https://www.labsmart.cn/ntp/salivary-gland-duct-metaplasia-squamous.html
- 中文图谱总页锚点：https://www.labsmart.cn/ntp-atlas.html#salivary-gland-duct-metaplasia-squamous
- 原始出处：https://ntp.niehs.nih.gov/atlas/nnl/alimentary-system/salivary-gland/Duct-MetaplasiaSquamous
- 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
化生（metaplasia）是一种终末分化细胞类型被同一胚层的另一种细胞类型所取代的改变。

## 病变描述（中文）
化生（metaplasia）是一种终末分化细胞类型被同一胚层的另一种细胞类型所取代的改变。通常，一种特化的上皮类型被分化程度较低的上皮类型所取代。化生常常（但并非总是）是响应反复上皮损伤而发生的适应性改变，因此常伴有其他病变，如炎症或坏死。如果去除病因，鳞状化生（squamous metaplasia）可能是可逆的。鳞状化生是化生的一种常见形式，推测是因为鳞状上皮比其他形式的上皮更能抵抗损伤。鳞状化生通常是慢性刺激的结果，但也可能有其他原因（例如维生素A缺乏症）。在唾液腺导管中，已观察到正常立方导管上皮在化学物质、电离辐射、病毒感染、维生素A缺乏以及唾液腺结石阻塞导管的作用下发生化为复层鳞状上皮。导管上皮的鳞状化生可能是进展为鳞状细胞癌的癌前病变。

## 诊断与分级建议（NTP 共识，中文）
唾液腺导管的鳞状化生应当根据受累区域的数量和鳞状上皮的厚度进行诊断和分级。相关病变，如炎症、坏死或变性，应当单独诊断。

## 英文原文 · Comment
Metaplasia is a change in which one terminally differentiated cell type is replaced by another cell type of the same germ line. Usually, a specialized type of epithelium is replaced by less specialized type of epithelium. Metaplasia is often, but not always, an adaptive change that occurs in response to repeated epithelial damage and is therefore often accompanied by other lesions such as inflammation or necrosis. Squamous metaplasia may be reversible if the cause is removed. Squamous metaplasia is a common form of metaplasia, presumably because squamous epithelium is more resistant to damage than other forms of epithelia. Squamous metaplasia is usually the result of chronic irritation, but it can have other causes (e.g., hypovitamnosis A). In the salivary ducts, metaplasia of the normally cuboidal ductal epithelium to stratified squamous epithelium has been seen in response to chemicals, ionizing radiation, viral infections, vitamin A deficiency, and blockage of ducts by salivary calculi. Squamous metaplasia of the ductular epithelium may be a preneoplastic lesion progressing to squamous cell carcinoma.

## 英文原文 · Recommendation
Squamous metaplasia of the salivary duct should be diagnosed and graded based on the number of areas involved and the thickness of the squamous epithelium. Associated lesions, such as inflammation, necrosis, or degeneration, should be diagnosed separately.

## 配图
- https://www.labsmart.cn/ntp-atlas-images/ntp_0043.jpg
- https://www.labsmart.cn/ntp-atlas-images/ntp_0046.jpg

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