Tumor

A tumor (plural tumors, also colloquially tumors; . Tumor from the Latin, - oris, m, proliferation ',' lump ',' swelling ') in a broader sense, any increase in the volume of tissue of higher organisms, regardless of the cause. Synonyms in a second, narrower meaning, the terms neoplasia (, formation ') and " greenhouse ".

Accordingly, in medicine, there are two definitions of tumor:

• In the broader sense of any increased space requirement ( mass ) of a tissue ( intumescent ) or a palpable induration, such as a swelling in inflammation (edema, cellulitis, abscess) or cyst ( see also pseudo- tumor), or even a chair accumulation in intestine, which can often grope in the left lower abdomen before stool. So it's a pretty fuzzy concept.
• In the narrow sense neoplasms of body tissues ( neoplasia ), caused by dysregulation of cell growth - which with respect to the goodness or evilness ( dignity ) is the formation testified anything yet.

Neoplasms can affect any type of tissue, they may be benign (benign) or cancerous (malignant ) be. The malignant variant is also colloquially referred to as cancer. Neoplasms may stand alone ( " solitary " ) or more times at different points in the body ( " multicentric " or " multifocal " ) occur. Usually, tumors are referred to as multicentric if the distance between the individual lesions is more than five centimeters and as multifocal if the distance is two inches or less, but there is no exact radiological definition for these terms. Depending on the location ( localization ) of the tumor and the function of the damaged tissue through him they can lead to destruction of organs with impairment of the whole organism until death.

Tumors occur ( in plants ) in all higher organisms. In this article, however, exclusively, received on tumors in humans, ie to the human medical importance.

Classification ( neoplasia)

Dignity (property)

Tumors are tissue changes that are heritable, but generally not contagious in humans. Your classified according to their biological behavior and growth according to the tissue of origin of the neoplasm. Depending on the dignity of the tumor, that is its ability to form metastases, one distinguishes benign (benign ), malignant (malignant) and semi-malignant tumors. The malignant tumors are further subdivided into low grade and high grade tumors.

• Benign (benign ) tumors displace by their growth surrounding tissue, by not grow ( infiltrate ) but it and do not form metastases.
• Malignant tumors are malignant tumors. These tumors are often referred to as cancer. They grow into surrounding tissue and destroy it, also put them through dissemination via the blood ( hematogenous ), the lymph ( lymphatic ) or by dripping of example, in the abdomen secondary tumors. Typical malignant tumors of the colon and lung cancer.
• Semi Malignant tumors usually put no secondary tumors, but destroy nearby tissue and grow into it ( destruction and infiltration).

Low mitotic activity

System

Benign tumors and malignant tumors are semi further differentiated according to their origin. The appointment shall be made by the appended suffix "- om " to the Latin name of the tissue of origin.

Malignant tumors are also - as far as the original tissue still visible and the tumor is not completely de-differentiated - named after this original tissue. However, this nomenclature is not held consistently, so that other terms are used for them (eg signet ring cell carcinoma after the appearance of the tumor cells). Malignant tumors are cancer referred to as the German (even if cancer is the translation of the Latin word ' carcinoma ', and thus only one - albeit the most common - group is called malignant tumors).

Malignant tumors can arise from not malignant precursors, so-called precancerous lesions develop. These are divided into facultative and obligate precancerous lesions.

The malignant tumors are subdivided as follows:

• Carcinomas describe malignant tumors derived from epithelium. They make up a large proportion of cancers.
• Sarcomas (Greek σάρκα, sarcastic, meat) that are derived from the connective and supporting tissue and can be classified according to the origin further, eg in rhabdomyosarcoma (cancer of striated muscle ), angiosarcoma (cancer of the blood vessels), leiomyosarcomas ( cancer of the smooth musculature, for example, rare forms of cervical cancer ), etc.
• Neuroendocrine tumors derived from the neuroectoderm. Examples include pheochromocytoma and insulinoma, but also small-cell lung cancer.
• Hämatoonkologische malignancies derived from blood or blood stem cells and are further differentiated into: Leukemia ( other than cancer )
• Lymphomas.

• Teratomas from embryonic tissue (all three germ layers ).
• Embryonic tumors (arise during organ development by tissue misdifferentiation )

The further classification of malignant tumors is analogous to the TNM classification of the UICC. It is a clinical- empirical classification which determines the further diagnosis, therapy and prognosis of malignant tumors.

Nomenclature of tumors

Source

Classification according to WHO

Tumors according to WHO graduated ( TNM classification ): T: tumor, N: Nodus ( lymph nodes), M: metastases ( distant metastases), R: resection (residual tumor). G: Grading

T classification ( tumor size ):

• T 1-3: Tumor is limited to the output member
• T4: Tumor invades other organs

N- classification ( lymph nodes):

• Absence or presence of regional lymph node metastases

M classification ( metastases):

• Presence or absence of distant metastases 0-1

R classification (resection ):

• Microscopic resection = 0 (no residual tumor )
• Microscopic resection = 1 ( residual tumor present)
• Resection with macroscopic residual tumor remnants residues = 2

G classification (grading):

• G1 to G4 good differentiation ( the original tissue similar ) to highly malignant

The localization of the tumors is the essential basis of the classification of neoplasms in the issued by the WHO International Statistical Classification of Diseases and Related Health Problems (ICD -10). See also: List of neoplasms according to ICD-10.

Formation

Tumors caused by degeneration, more precisely by an accumulation of mutations in specific genes ( engl. multiple hit model). These particular genes are proto-oncogenes or tumor suppressor genes typically. Alternatively, a degeneration by oncoviruses and oncogenic bacteria occur in which a continuous stimulation with cytokines by the immune response, and with growth factors occurs to replace the damaged cells, such as the hepatitis B virus. By a frequent cell division, the emergence of mutations in the copying of the genome is favored. Some persistent viruses ( the genomically -integrating viruses) is in addition an insertion through the insertion of the viral genome into the genome of the host, which usually is done in the deployed and active regions of the DNA transcription, such as retroviruses. In rare cases, a tumor will also be transmitted, eg by an organ transplant and the concomitant immunosuppression or - in dogs, bag devils and hamsters - by infectious tumors.

Effects of tumors on the body

Benign tumors grow slowly and usually do not affect the body. Some benign tumors can but mutate into malignant tumors. Here are primarily colonic polyps ( Kolonadenome ) call, which is very common to adenocarcinomas degenerate (so-called adenoma -carcinoma sequence ). However, hormone -producing adenomas can lead by their hormonal effects to serious diseases.

Complications of benign and malignant tumors are:

• Pressure atrophy by growth ( resulting eg in hormone deficiency in tumors in endocrine glands ).
• Mild obstruction by Lumina = installation of hollow organs with cyst formation.
• Ectopic hormone production, for example, of ACTH, parathyroid hormone or insulin.

Complications of malignant tumors are:

• Severe obstruction of hollow organs, such as: Bronchusverschluss → atelectasis, pneumonia.
• Ösophagusverschluss → = dysphagia dysphagia.
• Biliary obstruction → jaundice = jaundice.
• Intestinal obstruction → ileus.

Therapy

The tumor therapy is carried out by operational tumor removal (resection, even Wachkraniotomie in certain brain tumors), exposure to ionizing radiation and / or ( poly) chemotherapy.

In some certain malignant tumors, there are additional, specific treatment options. Against Malignant melanoma, the so-called black skin cancer, there is the stage of development of cancer immunotherapies located, in which the body is with special surface antigens, ie cellular features of malignant melanoma vaccinated. A similar concept is in some tumors, such as the gastrointestinal stromal tumors, with treatment followed by immune modulators, in which the body's immune system is stimulated, to be directed against tumor cells. Other tumors are additionally treated with local heat, by the bonding of the hepatic vessels or with locally administered poisons. These treatment options are all but reserved certain malignant tumors and constitutes only a small part of the therapy carried out. It is known that the tumor vaccination against melanoma in dogs has at least the same therapeutic success as chemotherapy, but this at much lower or no side effects ( I. Kurzman, University of Wisconsin, Madison ). In horses, there are already a number of positive experiences in malignant tumors and sarcoids with a vaccine with dendritic cells.

Epidemiology

Malignant tumors ( here esp. cancer) are in accordance with the cardiovascular disease is the second leading cause of death in industrialized countries.

Benign tumors are very common. Most people have several benign tumors, particularly to the skin. Some primary benign tumors can degenerate into malignant tumors and must be removed. This is the case especially with polyps of the colon mucosa. Often people feel benign tumors of the skin as cosmetically disturbing, sometimes these may be tempted, for example, in body folds, so that here a distance seems to make sense.