癌前病变和癌前状态

定义：

• 癌前病变（precancerous lesion）：是指具有形态学改变的组织，这种组织较其对应的、明显正常的组织，更容易发生癌。（A precancerous lesion is defined as morphologically alered tissue in which the development of malignancy is more likey than with normal mucosa.）
• 癌前状态（precancerous conditions）：是指伴随着癌的危险性明显增高的一种常态（general state）。（A precancerous condition is a condition or generalized disease that does not necessarily alter the appearance of the mucosa but may be associated with a greater rish for the development of cancer.）

上皮异常增生诊断标准：

Architectural changes	Cytological changes
Irregular epithelial stratification	Abnormal variation in nuclear size
Loss of polarity of basal cells	Abnormal variation in nuclear shape
Drop-shaped rete ridges	Abnormal variation in cell size
Increased number of mitotic figures	Abnormal variation in cell shape
Abnormally superficial mitotic figures	Increased N:C ratio
Premature keratinization in single cells	Atypical mitotic figures
Keratin pearls within rete ridges	Increased number and size of nucleoli
Loss of epithelial cell cohesion	Hyperchromasia

对于上皮增生的分级有多种方案，WHO根据上皮异常增生的范围，将其分为轻、中、重度上皮异常增生：

• 轻度：局限于上皮下1/3；
• 中度：扩展至上皮中1/3，但不超过上皮全层的2/3；
• 重度：超过2/3但未波及上皮全层。
• 原位癌：波及上皮全层但基底膜仍完整时即原位癌。

WHO于2005年对癌前病变和癌前状态的概念进行了简化，将其统称为"potentially malignant disorders"，并将其定义为"clinical presentations that carry a risk of cancer development in the oral cavity, whether in a clinically definable precursor lesion or in clinically normal mucosa."

Oral Potentially Malignant Disorders:

• Erythroplakia
• Erythroleukoplakia
• Leukoplakia
• Oral submucous fibrosis
• Dyskeratosis congenita
• Smokeless tobacco keratosis
• Palatal lesions associated with reverse smoking
• Chronic candidiasis
• Lichen planus
• Discoid lupus erythematosus
• Syphilitic glossitis
• Actinic keratosis (lip only)