一、鳞状上皮
表层和中间层鳞状上皮均为大多角形细胞,胞浆粉红色或绿色,中间层细胞核稍大。
副基底细胞和基底细胞为未成熟鳞状上皮细胞,正常情况下位于鳞状上皮的深部,一般取材时取不到,而未成熟上皮完全由副基底细胞和基底细胞构成,多见于移行区,称为鳞状化生,也可见于低雌激素状态时的鳞状上皮萎缩,因此,TCT中所见的副基底细胞和基底细胞常是取自鳞状化生或萎缩的上皮。副基底细胞为圆形或卵圆形,核大小不一,但常大于中间层细胞,基底细胞更小,胞质少。
基底和副基底细胞是萎缩的标志,萎缩较明显的TCT中,可看不到表层和中间层细胞,而仅见基底和副基底细胞。此外,萎缩的上皮易于损伤和发生炎症,特别是绝经后女性,其继发的形态学改变不要与有意义的病变相混淆。片状未成熟细胞拥挤,呈合体细胞样,与HSIL相似(Fig.1.6),但其染色质精细,分布均匀,核形光滑,且薄。罕见的移行细胞化生表现为显著的延长轴方向的核沟(咖啡豆样核),核皱褶及小的核周围空晕(Fig.1.6B)。部分萎缩病例尚可见细胞退变(Fig.1.7A)。风干可导致人为的核增大假象。有时可见由无定形物质构成的深蓝色团块,可能为致密的黏液或退变的细胞核(Fig.1.7B),由于有颗粒状背景,很像浸润癌中的坏死(Fig.1.7A)。
描述:Figure 1.6 Parabasal cells (postmenopausal smear). A, Atrophic epithelium is composed almost exclusively of parabasal cells, often arranged in broad, flowing sheets. B, Transitional cell metaplasia. In this uncommon condition, the atrophic epithelium resembles transitional cell epithelium by virtue of its longitudinal nuclear grooves. Nuclear membrane irregularities raise the possibility of a high-grade squamous intraepithelial lesion (HSIL), but the chromatin is pale and finely textured.
描述:Figure 1.7 Parabasal cells (postmenopausal smear). A, Degenerated parabasal cells in atrophic smears have hypereosinophilic cytoplasm and a pyknotic nucleus. Note the granular background, which is commonly seen in normal atrophic smears. B, Dark blue blobs are seen in some atrophic smears. These featureless structures should not be interpreted as a significant abnormality.
副基底细胞也是宫颈鳞状化生的组成部分。组织学上显示为扁平的片状未成熟鳞状上皮细胞,镶嵌状排列,似铺路石样(Fig.1.8),副基底细胞可表现出轻度的核大小不一,核稍不规则和轻度深染。
Figure 1.8 Squamous metaplasia. Interlocking parabasal-type cells, as seen here, represent squamous metaplasia of the endocervix.
细胞学所定义的鳞状化生由副基底细胞构成(未成熟鳞状上皮细胞)。组织学上描述的所谓的成熟性鳞状化生,在细胞学上可能无法识别。
其他的鳞状上皮良性改变还包括角化过度和角化不全。角化过度是黏膜慢性刺激的结果,例如子宫脱垂,TCT表现为无核的多角形成熟鳞状上皮细胞单个散在或成片分布(Fig.1.9)。部分可能与操作者污染有关。角化不全也与慢性刺激有关,表现为小的明显角化的鳞状上皮细胞,伴有深染的橘红色胞浆和小的固缩的核(Fig.1.9B)。若这些角化不全的细胞表现出核的非典型性,包括核增大、核膜不规则、深染,则称为角化不良细胞或非典型性角化不全,应认为是一种细胞学异常。
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描述:Figure 1.9 Keratosis. A, Hyperkeratosis. Anucleate squames are a protective response of the squamous epithelium. B, Parakeratosis. Parakeratosis appears as plaques, as seen here, or as isolated cells.