Morphogenesis and histogenesis of tumors

The concept of "morphogenesis"Covers the laws governing the formation and development of tumors in general.

Gistogenez It involves identifying tissue structure, from which he developed a tumor. Views on the morphogenesis of tumors recently changed significantly.

At first, considered, that tumors tend not uni-, a multicentric development, Although multiple points of growth usually merge into one unit.

Secondly, tumor arises not from a small focus of cells, and the field of tumor, which can occupy a portion of body.

Third, According to the theory of progression, the acquisition of tumor properties occurs phasically. For Example, cancer may first develop precancerous hyperplasia, then carcinoma in situ, later turning into invasive cancer. In the field there is no tumor metastasis.

The doctrine of the tumor field zones, consistently be involved in the neoplastic process, It provides a new understanding of the mechanism of relapse. It was previously thought, that tumor cells can only originate from tumor cells, therefore relapse due to incomplete removal or destruction of the tumor. Recurrences of this kind are possible, but more often they are caused by, that only the tumor is removed, tumor and the field is growing and from a new tumor by the same laws, that distant and.

With respect to tumor histogenesis especially attaches great importance to, organoid cancer, t. it is. Its properties are copying the structure of normal tissue, Authority. At the same time due to the repetition of anaplasia tissue structures becomes distorted form. Despite the above feature, on histological, and in some cases the tumor and cytological preparations can often determine its source not only in the preparation of the body, but also in the metastatic foci.

However, in the process of tumor growth, the degree of histological structures never reaches the level of formation of the individual structural units of normal organ. So, If adenocarcinoma tumor in the structure of pronounced organoid, the other forms of tumors (nedifferentsirovannыy cancer) this property is largely lost. In such cases, tumor cells tend to lose the similarity with the original elements epithelium, however, they may retain some of their specific functional properties.

For Example, cancerous cells of the gastric mucosa can secrete mucus; cancer cells, develop from epithelial elements of the liver parenchyma, capable of producing bile, and cancer cells of the thyroid gland - colloid.

The structure of the tumor does not always determine its histogenesis. So, squamous cell carcinoma of the skin can not develop from the epidermis, and from the epithelium of the sebaceous glands by his metaplasia.

Adenocarcinoma of the stomach may be motivated ulcers, gastritis, polyp, and the definition of its histogenesis in each case causes difficulties.