Tumors [tumores; synonym: neoplasms (neoplasmata), blastoma (blastomata)] – excess, continued after the termination of its cause, is not coordinated with the body abnormal proliferation of tissue that consists of qualitatively altered cells become atypical with respect to differentiation and the nature of growth and pass these properties to their offspring. Malignant tumor – is tumor, having infiltrative-destructive nature of growth and significant anaplasia (see). NN Petrov called O. "unregulated excesses of focal cell division."
A number of features that define the essence of O. So, they emerge and develop as separate foci of the body tissues, but differ from the latter features of its growth and low differentiation (atypia or anaplasia anaplasia) of their constituent cells. In short we can say that the OS – a "plus cell proliferation, minus their differentiation." This property transmitted to the progeny of tumor cells. Tumor growth is excessive, relatively independent of the body – "autonomous." Malignant O. at growth can infiltrate, invade and destroy surrounding tissue. In contrast to various lumps and "false" O. caused by inflammation or circulatory disorders, the true O. augmented by breeding their own cells, and not by exudation and migration of cellular elements of the connective tissue. Another important feature of tumor growth, which distinguishes it from the regenerator, – inadequate degree of tissue damage and the fact that from the very beginning of the pathological rather than physiological process. Delete a part of it again O. growing, recurs, but is not involved in regeneration, in the construction of normal tissues. However, the tumor growth, Like any disease process, has its physiological prototype, which is manifested in the proliferation of cells and tissues caused by hormonal influences (eg, the introduction of chorionic villi in fabric uterus during pregnancy). In the latter case we can talk about the physiological and even prototype infiltrative destructive growth.
The occurrence of tumors in one or another organ or tissue begins as a small group changed and continues to change cells. O. development takes place gradually. There are several stages – the irregular diffuse hyperplasia, focal proliferation and the formation of so-called benign O., and finally, a possible malignancy as the latter, and focal proliferative. Sprawl immediately preceding malignant O. and her passing is called precancerous (see), and earlier changes in tissues can be considered precancerous. Further development of OA depends on the organism as a whole and can happen, apparently, only in case of violation of some correlative relationships. This is evidenced by the duration of the development of OA in humans and the possibility of metastasis many years after removal of the primary tumor (the so-called "dormant metastases"). However, despite the undoubted importance in the genesis of OA changes in the body as a whole, we can not forget that every OA starts with a local hot spot growths that tumor cells that have acquired new pathological properties, transfer them to their descendants and thus creates a new breed of cell what is the essence of the pathological process and the basis of the disease.
- Distribution in nature
- Statistics of human tumors
- Nomenclature, classification, structure and development
- The experimental study
- Principles of recognition and treatment
- Principles of prevention
- Organization of cancer care
- Features of tumors in children
Tumors (synonym: neoplasm, blastoma, tumors) are the excess growth of abnormal tissue, which continues after the termination of its cause. This proliferation is not coordinated with the body – it is offline. Proliferating cells that have become atypical in respect of differentiation and the nature of growth and pass these properties to their offspring.
From the clinical and morphological point of view, distinguish benign and malignant tumors.
The criterion is the nature of their growth. Benign O. grow slowly, only push, pushing, and sometimes compress the surrounding tissue, but no germination in them. Malignant tumors are different infiltrative growth – they grow into the surrounding tissue and destroy them. Related to this, and the possibility of tumor metastasis (see metastasis), characteristic of malignant tumors. With the destruction of blood vessels in them can reach tumor cells are addicted to the blood or lymph, are recorded in other tissues and organs and can reproduce it and form a secondary, ie, metastatic, node. Benign tumors do not metastasize.
However, they can be dangerous if you compress the vital centers in the brain and spinal cord, or respiratory or digestive track. If the surgery removed part of a benign tumor, it may increase again, to recur.
Tumors occur in animals of all classes and types: fish, amphibians, reptiles, birds and all mammals and man.
A. composed of parenchyma and stroma. Parenchyma is own tissue tumors represent its mass and establishes its growth and character. Stroma – layer of connective tissue, which are vessels and nerves.
In the nomenclature of tumors reflected their tissue origin: the end of the "Ohm" (from the Greek word "onkoma" – tumor) attached to the roots of words for a particular tissue. Swelling of cartilage called chondroma, tumor of adipose tissue – lipoma of muscle – fibroids, etc. Some tumors remain historically entrenched special name for them. Malignant tumor of connective tissue called sarcoma (see) because the context of its fabric fish-like meat (Greek sarkos – meat). Malignant epithelioma is called "cancer" is probably due to the fact that the first observation of the ancient doctors treat breast cancer or skin, germinate in the surrounding tissue strands that resemble the claws of cancer. In many countries, for example France, the term "cancer" (UCR) applies to all malignant, O., and in the USSR and other countries cancer is called a malignant epithelial tumor (see Cancer).
Pathoanatomical classification of tumors based on their belonging to a particular tissue: There are epithelial, connective, muscle and nerve tumors. Epithelial tumors are divided into originating from glandular epithelium and flat. If the structure of the visible tumor glands, it is called an adenoma, and malignant – adenocarcinoma. Connective tumor depending on the type of fabric can be divided into fibroma, lipoma, chondroma, osteoma.
A. Some called for the body or parts of it, such as hepatoma – a tumor of the liver cells, insuloma – of pancreatic islet tissue, etc.
Malignant tumors tend to develop, out of the preceding them relatively benign growths, which are called pre-cancerous (see pre-cancer). Thus, there is a gradual development of the tumor, its kind of progression. If the disease has not been detected in a timely manner and were not used due care treatment, the progression of the tumor and its metastasis, the destruction of vital organs, failure of important life-ways, such as the digestive or respiratory, anemia due to bleeding from the ulcerated tumor, general poisoning body decay products tumor and metabolic disorders – can lead to a significant depletion, called cachexia (see).
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