This is a commonly used medical term for tumor pathology. The following are the introductions: hyperplasia: generally refers to the increase of tissue cells, often accompanied by cell hypertrophy, which causes physiological or pathological changes of tissues and cells under the action of some stimulating factors. In the covered epithelium, epithelial tissues tend to thicken and cells increase; In mesenchymal tissue, cells are often increased and arranged closely, but there is no type. Once the stimulus is removed, it can return to normal state.
Atypical hyperplasia: also known as dysplasia, anaplasia or nuclear dysplasia, it can be found in any tissue or cell, and its morphological manifestations are relatively enlarged nucleus, thickened nuclear membrane, irregular nuclear shape and increased ratio of nuclear cytoplasm, but it does not have the morphological characteristics of malignant tumor. It belongs to a kind of precancerous lesion. Under the continuous action of some factors, it can change from quantitative change to qualitative change and become malignant tumor. If some factors are removed, it may return to normal state. According to the degree of lesions, atypical hyperplasia is generally divided into mild, moderate and severe. Severe hyperplasia is precancerous lesion. Cancer in situ: also known as intraepithelial cancer, pre-invasion cancer, etc. When atypical epithelial cells develop further, the nuclear atypia is more obvious, the nuclear shape is irregular, the nuclear membrane is thickened, the chromatin is thickened, the nucleoli is prominent, and mitosis is increased. This abnormal epithelial tissue has involved the whole epithelial layer, but it has not invaded the basement membrane. It is the earliest cancer and irreversible. Metaplasia: Usually refers to a kind of cell or tissue, which changes from one tissue to another under the action of some factors. For example, when the cervix is severely eroded, the columnar epithelium or glandular epithelium covered by the cervical canal can be transformed into squamous epithelium, which is called squamous metaplasia.
It is generally believed that metaplasia is usually a protective reaction of organs or tissues, and this squamous metaplasia's canceration is rare, so it should not be treated as a precancerous lesion. Tumor-like lesions: Some tissues grow and look like tumors, but sometimes it is difficult to distinguish them from real tumors. This is a large group of proliferative lesions that look like tumors, such as vegetations, keloids, fat pads, etc. Some tumor-like lesions of tissues can be transformed into real tumors, such as pigmented villonodular synovitis, which can be transformed into synovial sarcoma. Therefore, this kind of lesions should be treated as precancerous lesions.