Benign tumor

WikiDoc Resources for Benign tumor
Articles
Most recent articles on Benign tumor Most cited articles on Benign tumor Review articles on Benign tumor Articles on Benign tumor in N Eng J Med, Lancet, BMJ
Media
Powerpoint slides on Benign tumor Images of Benign tumor Photos of Benign tumor Podcasts & MP3s on Benign tumor Videos on Benign tumor
Evidence Based Medicine
Cochrane Collaboration on Benign tumor Bandolier on Benign tumor TRIP on Benign tumor
Clinical Trials
Ongoing Trials on Benign tumor at Clinical Trials.gov Trial results on Benign tumor Clinical Trials on Benign tumor at Google
Guidelines / Policies / Govt
US National Guidelines Clearinghouse on Benign tumor NICE Guidance on Benign tumor NHS PRODIGY Guidance FDA on Benign tumor CDC on Benign tumor
Books
Books on Benign tumor
News
Benign tumor in the news Be alerted to news on Benign tumor News trends on Benign tumor
Commentary
Blogs on Benign tumor
Definitions
Definitions of Benign tumor
Patient Resources / Community
Patient resources on Benign tumor Discussion groups on Benign tumor Patient Handouts on Benign tumor Directions to Hospitals Treating Benign tumor Risk calculators and risk factors for Benign tumor
Healthcare Provider Resources
Symptoms of Benign tumor Causes & Risk Factors for Benign tumor Diagnostic studies for Benign tumor Treatment of Benign tumor
Continuing Medical Education (CME)
CME Programs on Benign tumor
International
Benign tumor en Espanol Benign tumor en Francais
Business
Benign tumor in the Marketplace Patents on Benign tumor
Experimental / Informatics
List of terms related to Benign tumor

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Overview

A benign tumor is a tumor that lacks all three of the malignant properties of a cancer. Thus, by definition, a benign tumor:

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.

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).

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.

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).

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).

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.

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

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.

References

Template:Tumors