A benign tumor is a tumor that lacks all three of the malignant properties of a cancer. Thus, by definition, a benign tumor: For malignant tumors specifically, see cancer. ... In medicine, malignant is a clinical term that means to be severe and become progressively worse, as in malignant hypertension. ... Cancer is a class of diseases or disorders characterized by uncontrolled division of cells and the ability of these to spread, either by direct growth into adjacent tissue through invasion, or by implantation into distant sites by metastasis (where cancer cells are transported through the bloodstream or lymphatic system). ...

1. does not grow in an unlimited, aggressive manner
2. does not invade surrounding tissues
3. does not metastasize

Common examples of benign tumors include moles and uterine fibroids. Biological tissue is a group of cells that perform a similar function. ... Metastasis (Greek: change of the state) is the spread of cancer from its primary site to other places in the body. ... A mole, technically known as a melanocytic naevus, is a small, dark spot on human skin. ... A leiomyoma (plural is leiomyomata) is a benign smooth muscle neoplasm that is not premalignant. ...

The term "benign" implies a mild and nonprogressive disease, and indeed, many kinds of benign tumor are harmless to the health. However, some neoplasms which are defined as 'benign tumors' because they lack the invasive properties of a cancer, may still produce negative health effects. Examples of this include tumors which produce a "mass effect" (compression of vital organs such as blood vessels), or "functional" tumors of endocrine tissues, which may overproduce certain hormones (examples include thyroid adenomas, adrenocortical adenomas, and pituitary adenomas). Look up Benign in Wiktionary, the free dictionary. ... The endocrine system is a control system of ductless endocrine glands that secrete chemical messengers called hormones that circulate within the body via the bloodstream to affect distant organs. ... For other uses, see Hormone (disambiguation). ... A thyroid adenoma, or solitary thyroid nodule is a benign tumor of the thyroid gland. ... Pituitary adenomas are tumors that occur in the pituitary gland, and account for about 10% of intracranial neoplasms. ...

Benign tumors typically are encapsulated, which inhibits their ability to behave in a malignant manner. Nonetheless, many types of benign tumors have the potential to become malignant and some types, such as teratoma, are notorious for this. A capsule, in anatomy, is a cover or envelope partly or wholly surrounding a structure. ... In medicine, malignant is a clinical term that means to be severe and become progressively worse, as in malignant hypertension. ... Look up teratoma in Wiktionary, the free dictionary. ...

Classification

The term "tumor" literally means "swelling", and the broadest definition of "benign tumor" encompasses all abnormal tissue masses which are not cancers. In practice, most of these entities are neoplasms, meaning that they contain a discrete population of cells which proliferate in an independent manner, usually as the result of acquired genetic abnormalities. Entities which may be referred to as "tumors" but are non-neoplastic include developmental abnormalities, such as hamartomas and ectopic rests (normal tissue in an anatomically abnormal location).^[1] Cancer is a class of diseases or disorders characterized by uncontrolled division of cells and the ability of these to spread, either by direct growth into adjacent tissue through invasion, or by implantation into distant sites by metastasis (where cancer cells are transported through the bloodstream or lymphatic system). ... Neoplasia (literally: new growth) is sudden and abnormal growth in a tissue or organ. ... This article is about the general scientific term. ... A hamartoma is a common benign tumor in an organ composed of tissue elements normally found at that site but that are growing in a disorganized mass. ...

Benign neoplasms are typically composed of cells which bear a strong resemblance to a normal cell type in their organ of origin. These tumors are named for the cell or tissue type from which they originate, followed by the suffix "-oma" (but not -carcinoma, -sarcoma, or -blastoma, which are generally cancers). For example, a lipoma is a common benign tumor of fat cells (lipocytes), and a chondroma is a benign tumor of cartilage-forming cells (chondrocytes). Adenomas are benign tumors of gland-forming cells, and are usually specified further by their cell or organ of origin, as in hepatic adenoma (a benign tumor of hepatocytes, or liver cells). There are a few cancers with 'benign-sounding' names which have been retained for historical reasons, including melanoma (a cancer of pigmented skin cells, or melanocytes) and seminoma (a cancer of male reproductive cells).^[1] A lipoma is a common, benign tumor composed of fatty tissue. ... A chondroma is a benign cartilaginous tumor, which is encapsulated with a lobular growing pattern. ... Hepatocellular adenoma or Hepadenoma is an uncommon benign liver tumour which is associated with the use of oral contraceptive pills with a high oestrogen content. ... Sinusoid of a rat liver with fenestrated endothelial cells. ... The liver is the largest internal organ in the human body, and is an organ present in vertebrates and some other animals. ... Melanoma is a malignant tumor of melanocytes which are found predominantly in skin but also in the bowel and the eye (see uveal melanoma). ... Melanocytes are cells located in the bottom layer of the skins epidermis. ... Testicular cancer is a type of cancer that develops in the testicles, a part of the male reproductive system. ...

In some cases, certain "benign" tumors may later give rise to malignant cancers, which result from additional genetic changes in a subpopulation of the tumor's neoplastic cells. A prominent example of this phenomenon is the tubular adenoma, a common type of colon polyp which is an important precursor to colon cancer. The cells in tubular adenomas, like most tumors which frequently progess to cancer, show certain abnormalities of cell maturation and appearance collectively known as dysplasia. These cellular abnormalities and are not seen in benign tumors that rarely or never turn cancerous, but are seen in other pre-cancerous tissue abnormalities which do not form discrete masses, such as pre-cancerous lesions of the uterine cervix. Some authorities prefer to refer to dysplastic tumors as "pre-malignant", and reserve the term "benign" for tumors which rarely or never give rise to cancer. A polyp is an abnormal growth of tissue (tumor) projecting from a mucous membrane. ... Dysplasia (from Greek, roughly: bad form) is a term used in pathology to refer to an abnormality in maturation of cells within a tissue. ... Cervical intraepithelial neoplasia, or CIN, is the abnormal growth of precancerous cells in the cervix. ...

Signs and symptoms

Benign tumors are very diverse, and may be asymptomatic or may cause specific symptoms depending on their anatomic location and tissue type. Symptoms or pathological effects of some benign tumors may include:

• Bleeding or occult blood loss causing anemia
• Pressure causing pain or dysfunction
• Cosmetic changes
• Itching
• 'Hormonal syndromes' resulting from hormones secreted by the tumor
• Obstruction, e.g., of the intestines
• Compression of blood vessels or vital organs

For other uses, see Occult (disambiguation). ... This article discusses the medical condition. ... Bowel obstruction is a mechanical blockage of the intestines, preventing the normal transit of the products of digestion. ...

Treatment

Many benign tumors do not need to be treated at all. If a benign tumor is causing symptoms, presents a health risk, or causes a cosmetic concern for the patient, surgery is usually the most effective approach. Most benign tumors do not respond to chemotherapy or radiation therapy, although there are exceptions. “Surgeon” redirects here. ... Chemotherapy, in its most general sense, refers to treatment of disease by chemicals that kill cells, specifically those of micro-organisms or cancer. ... Varian Clinac 2100C Linear Accelerator Radiation therapy (or radiotherapy) is the medical use of ionizing radiation as part of cancer treatment to control malignant cells (not to be confused with radiology, the use of radiation in medical imaging and diagnosis). ...

References