上皮鳞状化生Epithelium Metaplasia Squamous · 鼻 · 呼吸系统 · NTP ntp-0128
诊断要点：鼻上皮的鳞状化生无论何时出现均应作出诊断并赋予严重程度分级。受累及的上皮应作为部位修饰词纳入诊断。
病变描述
鳞状化生（squamous metaplasia）（Figure 1、Figure 2、Figure 3、Figure 4、Figure 5）定义为移行上皮、呼吸上皮或嗅上皮被鳞状上皮取代。该病变在对照动物中罕见，但在刺激性物质的吸入研究中相对常见。早期变化包括上皮细胞排列紊乱，表层细胞相对于基底膜呈水平方向排列。该病变必须与再生相鉴别，再生通常为1或2层细胞厚度。然而，在通常仅有2或3层细胞的移行上皮中，这种区分可能较为困难。移行上皮中表层细胞极性的改变可能是鳞状化生的唯一指征。在严重病变中，化生上皮可能明显增厚，并可能出现网嵴形成或角化。化生性改变可累及上皮下腺体的导管或鼻泪管。鳞状化生被认为是一种适应性改变，因为鳞状上皮比其他上皮类型更能抵抗损伤。化生上皮可能含有异型性区域，这些区域可能是癌前病变。随着暴露停止，鳞状化生可能是可逆的，但在慢性研究中，取决于受试物的性质，鳞状化生可能发展为鳞状细胞乳头状瘤或鳞状细胞癌。
诊断与分级建议（NTP 共识）
鼻上皮的鳞状化生无论何时出现均应作出诊断并赋予严重程度分级。受累及的上皮应作为部位修饰词纳入诊断。其他病变，如炎症，在严重程度需要时应当单独诊断。如存在，鲍曼腺扩张和嗅神经萎缩应在叙述中描述，除非该病变足够显著而需要单独诊断（见 Nose - Olfactory Epithelium, Glands - Metaplasia）。角化可能是鳞状化生的一个组成部分，无需单独诊断；但应在叙述中描述。化生性鳞状上皮可能含有相对于未受影响鳞状上皮的增生特征（例如增厚、网嵴形成），这些特征也应在叙述中描述。如存在异型性特征，应通过添加修饰词“非典型性（atypical）”作出诊断。相关链接：Nose - Olfactory Epithelium, Glands - Metaplasia
图谱
英文原文
展开 NTP 官方英文描述与建议
Comment：
Squamous metaplasia ( Figure 1 , Figure 2 , Figure 3 , Figure 4 , and Figure 5 ) is defined as the replacement of transitional, respiratory, or olfactory epithelium by squamous epithelium. It is rarely seen in control animals but is relatively common in inhalation studies of irritants. Early changes include disorganization of the epithelial cells, with the superficial cells becoming oriented horizontally with respect to the basal lamina. This lesion must be differentiated from regeneration, which is typically 1 or 2 cell layers thick. However, in the transitional epithelium, which normally has only 2 or 3 cellular layers, this distinction can be difficult. The change in polarity of the superficial cells in the transitional epithelium may be the only indication of squamous metaplasia. In severe lesions, the metaplastic epithelium may be quite thickened, and there may be rete peg formation or keratinization. The metaplastic change can affect the ducts of subepithelial glands or the nasolacrimal ducts. Squamous metaplasia is considered an adaptive change, since squamous epithelium is more resistant to injury than are the other epithelial types. The metaplastic epithelium may contain areas of atypia, which may be preneoplastic. With cessation of exposure, squamous metaplasia may be reversible, but in chronic studies, depending on the nature of the test article, squamous metaplasia may give rise to squamous cell papilloma or squamous cell carcinoma.
Recommendation：
Squamous metaplasia of the nasal epithelium should be diagnosed whenever present and assigned a severity grade. The affected epithelium should be included in the diagnosis as site modifier. Other lesions, such as inflammation, should be diagnosed separately when warranted by severity. If present, Bowman’s gland dilation and olfactory nerve atrophy should be described in the narrative, unless the lesion is prominent enough to warrant a separate diagnosis (see Nose - Olfactory Epithelium, Glands - Metaplasia ). Keratinization may be a component of squamous metaplasia and need not be diagnosed separately; however, it should be described in the narrative. Metaplastic squamous epithelium may contain features of hyperplasia relative to unaffected squamous epithelium (e.g., thickening, rete peg formation), and these features should also be described in the narrative. If features of atypia are present, it should be diagnosed by adding the modifier, "atypical." Related Links: Nose - Olfactory Epithelium, Glands - Metaplasia
来源与引用
原始条目：https://ntp.niehs.nih.gov/atlas/nnl/respiratory-system/nose/Epithelium-MetaplasiaSquamous
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. Epithelium Metaplasia Squamous (nose). LabSmart 中文版：
https://www.labsmart.cn/ntp/nose-epithelium-metaplasia-squamous.html
中文图谱总页（可展开对照全部 595 条）：https://www.labsmart.cn/ntp-atlas.html#nose-epithelium-metaplasia-squamous