5) The growth of metastasis.

The main types of metastases, based on the pathways of metastasis, are as follows:

• Lymphogenic

• Hematogenic

• Implantation

• Mixed.

Some histogenetic groups of tumors (for example, sarcomas) are characterized by hematogenous metastases, while others (for example, cancer) are characterized by lymphogenic metastases. Metastases tend to grow faster than the main tumor, and therefore are often larger than it. The time required for the development of metastases varies. In some cases, metastases appear very quickly, following the appearance of the primary node, in others they develop several years after its appearance. There are also so-called latent or dormant metastases, which can develop 7-10 years after radical removal of the primary tumor.

Dormant metastases are tumor cells that spread throughout the body and can remain inactive (or at least grow very slowly) for many years. To destroy such metastases, after radical surgical treatment of the primary focus, a course of chemotherapy is required.

Localization of metastases. Metastases are localized most often at the site of the first capillary network, which is formed from vessels carrying blood from the site of the primary localization of the tumor. Some types of cancer have characteristic metastasis sites, although the exact mechanisms of this are unknown. The reason for stopping the tumor embolus may be purely mechanical – the diameter of the vessel turns out to be smaller than the diameter of the tumor cell, but the place of stopping the tumor embolus may also be determined by the fact that there are special receptors on the surface of the vessels of various organs that may be related to tumor cells.

Most often, metastases develop in the lymph nodes, liver, and lungs. Rarely – in the heart muscle, skeletal muscles, skin, spleen, pancreas. The central nervous system, bone system, kidneys, and adrenal glands occupy an intermediate place in terms of the frequency of localization of metastases. Cancers of the prostate, lung, breast, thyroid and kidney most often metastasize to the bones, lung cancer to the adrenal glands.

105. Local and general influence of the tumor on the body, examples.

The effect of a tumor on the body

Local - complications of tumor growth compression of tissues, including nerve trunks and plexuses (pain);

Purulent inflammation and ulceration;

gangrenous decay;

Bleeding, anemia;

Perforation of hollow organs

Violation of the patency of organs (gastric, intestinal obstruction, jaundice, hydronephrosis, hydrocephalus, etc.);

Organ failure

General effect on the body

Fever; Anemia;

Weight loss up to cachexia;

Paraneoplastic syndromes –

Endocrine - ectopic Itsenko-Cushing syndrome, hypercalcemia.

Cardiovascular and hematological (thrombosis, embolism, DIC syndrome, endocarditis)

Cutaneous

Nervous and muscular syndromes

106. Principles of classification of tumors. The role of the pathologist in the diagnosis of tumors.

The task of the pathologist is not only to confirm that there is a tumor in the examined material and to determine its degree of malignancy, but also to determine its exact histological type. According to the classification of the World Health Organization, neoplasms are divided by localization and there are more than 200 types for each organ

The classification of tumors is based on the following main criteria: degree of maturity (benign and malignant), histogenetic and cytogenetic affiliation (by cellular and tissue source of development), degree of differentiation (for malignant tumors).

The traditional and most common clinical and morphological classification divides all neoplasms into two important classes: benign and malignant.

Benign tumors, their properties:

they grow expansively, pushing apart and squeezing the surrounding tissues;

as a rule, they are clearly delimited and may have a fibrous capsule (pseudocapsule);

in hollow and tubular organs, they are more often characterized by an exophytic type of growth (they grow into the lumen);

They almost always grow slowly;

they do not give metastases;

they have tissue atypism, but do not have atypia and polymorphism of tumor parenchyma cells.

They are characterized by mitotic activity of the tumor parenchyma, rarely exceeding the limits of the corresponding norm.

Malignant tumors, their properties:

they have invasive (infiltrating) growth with the germination of surrounding tissues and their destruction;

in hollow and tubular organs, they are characterized by both exophytic and endophytic growth types;

They almost always grow fast;

they often metastasize;

they have tissue atypism, as well as atypism and polymorphism of tumor parenchyma cells;

They are often characterized by increased mitotic activity of the tumor parenchyma and the presence of necrosis zones.

The following classification is based on the histogenetic principle, taking into account the morphological structure, localization, structural features of tumors in individual organs, their goodness and malignancy. The term "tumor histogenesis" refers to the tissue origin of the tumor, which is not entirely accurate, since at present we can often determine not only the tissue, but also the cellular origin of the neoplasm, i.e. its cytogenesis. In some cases, on the contrary, even the histogenesis of the tumor remains unclear. The cytogenesis of tumors of hematopoietic and lymphoid tissue — hemoblastoses - has been particularly well studied. The theory of cytogenesis of hemoblastoses is based on the doctrine of stem and semi-stem cells-precursors of hematopoiesis.

Classification of tumors by histogenesis

Epithelial tumors without specific localization (organ-specific).

Tumors of the exo- and endocrine glands, as well as epithelial integuments (organ-specific).

Mesenchymal tumors.

Tumors of melanin-forming tissue.

Tumors of the nervous system and the membranes of the brain.

Tumors of the blood system.

Teratomas.

Histological gradation of malignant neoplasms according to the degree of differentiation of parenchyma is very important in clinical and prognostic terms.

Highlight:

— highly differentiated tumors: have parenchyma, which is closest in structure and function to its normal counterpart. Cellular atypism and polymorphism in them, as a rule, are poorly expressed. The tendency to growth, invasion and metastasis does not reach the maximum level;

— moderately differentiated tumors: these indicators are more pronounced, the degree of malignancy is higher;

— low-grade tumors: the signs listed above are particularly pronounced, which is realized in more significant malignant potentials.

Tumors with a lower degree of differentiation are less prognostically favorable.

The basic principles of tumor classification form the basis of the International Oncological Classification of Diseases (ICD-O), which is revised by the World Health Organization (WHO) every few years.

The staging of most malignant tumors (with the exception of lymphomas and some other tumors) is carried out according to the international TNM system.

In this system, the letter T (Timog) denotes the extent of local invasion in the area of the main tumor node, the letter N (Nodes) — involvement of regional lymph nodes in the metastatic process, the letter M (Metastases) — the presence of separated hematogenous metastases.

For example, breast cancer with widespread invasion of all its structures, widespread metastases to the lymph nodes and lungs, liver in the diagnosis should be encoded as T4N3M1. If the presence of metastases has not been established, but it is not excluded, the sign "x" (T4NxMx) is placed instead of the number.

Stages of cancer, designated as I, II, III. IV is recommended to be used only additionally, as needed.

+Secondary changes in tumors are represented by foci of necrosis and hemorrhages, inflammation, ossification, sclerosis, deposition of calcium salts (petrification), proliferation of bone structures (ossification), formation of cysts.

Sometimes these changes occur in connection with the use of radiation therapy and chemotherapy and are a sign of therapeutic pathomorphosis, therefore, when sending a biopsy or a removed tumor to the pathology department, the treatment must be indicated.