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Causes of Benign tumor
Causes of Benign tumor: Online Medical Books
16 MEDICAL BOOKS ONLINE! Review excerpts from medical books online, free, without registration, for more information about the causes of Benign tumor.
Malignant brain tumors:
Causes and incidence
(Professional Guide to Diseases (Eighth Edition))
The cause of most brain tumors is unknown, but exposure to ionizing radiation is a known environmental risk. Additionally, most malignant tumors of the brain are of metastatic origin; 20% to 40% of patients with cancer develop brain metastasis.
Malignant spinal neoplasms:
Causes and incidence
(Professional Guide to Diseases (Eighth Edition))
Primary tumors of the spinal cord may be extramedullary (occurring outside the spinal cord) or intramedullary (occurring within the cord itself). Extramedullary tumors may be intradural (meningiomas and schwannomas), which account for 60% of all primary malignant spinal cord neoplasms, or extradural (metastatic tumors from breasts, lungs, prostate, leukemia, or lymphomas), which account for 25% of these malignant neoplasms.
Intramedullary tumors, or gliomas (astrocytomas or ependymomas), are comparatively rare, accounting for only about 10%. In children, they're low-grade astrocytomas.
Spinal cord tumors are rare compared with intracranial tumors (ratio of 1:4). They occur equally in men and women, with the exception of meningiomas, which occur mostly in women. Spinal cord tumors can occur anywhere along the length of the cord or its roots.
Primary malignant bone tumors:
Causes and incidence
(Professional Guide to Diseases (Eighth Edition))
Causes of primary malignant bone tumors are unknown. Some researchers suggest that primary malignant bone tumors arise in areas of rapid growth because children and young adults with such tumors seem to be much taller than average. Additional theories point to heredity, trauma, and excessive radiotherapy.
For incidence information, see Comparing primary malignant bone tumors.
Introduction: Malignant Neoplasms:
What causes cancer?
(Professional Guide to Diseases (Eighth Edition))
Researchers have found that cancer develops from mutations within the genes of cells. Thus, cancer is a genetic disease. Cancer susceptibility genes are of two types. Some are oncogenes, which activate cell division and influence embryonic development, and some are tumor suppressor genes, which halt cell division.
These genes are typically found in normal human cells, but certain kinds of mutations may transform the normal cells. Inherited defects may cause a genetic mutation, whereas exposure to a carcinogen may cause an acquired mutation. Current evidence indicates that carcinogenesis results from a complex interaction of carcinogens and accumulated mutations in several genes.
In animal studies of the ability of viruses to transform cells, some human viruses exhibit carcinogenic potential. For example, the Epstein-Barr virus, the cause of infectious mononucleosis, has been linked to Burkitt's lymphoma and nasopharyngeal cancer.
High-frequency radiation, such as ultraviolet and ionizing radiation, damages the genetic material known as deoxyribonucleic acid (DNA), possibly inducing genetically transferable abnormalities. Other factors, such as a person's tissue type and hormonal status, interact to potentiate radiation's carcinogenic effect. Examples of substances that may damage DNA and induce carcinogenesis include:
❑alkylating agents — leukemia
❑aromatic hydrocarbons and benzopyrene (from polluted air) — lung cancer
❑asbestos — mesothelioma of the lung
❑tobacco — cancer of the lung, oral cavity and upper airways, esophagus, pancreas, kidneys, and bladder
❑vinyl chloride — angiosarcoma of the liver.
Diet has also been implicated, especially in the development of GI cancer as a result of a high animal fat diet. Additives composed of nitrates and certain methods of food preparation — particularly charbroiling — are also recognized factors.
The role of hormones in carcinogenesis is still controversial, but it seems that excessive use of some hormones, especially estrogen, produces cancer in animals. Also, the synthetic estrogen diethylstilbestrol causes vaginal cancer in some daughters of women who were treated with it. It's unclear, however, whether changes in human hormonal balance retard or stimulate cancer development.
Some forms of cancer and precancerous lesions result from genetic predisposition either directly (as in Wilms' tumor and retinoblastoma) or indirectly (in association with inherited conditions such as Down syndrome or immunodeficiency diseases). Expressed as autosomal recessive, X-linked, or autosomal dominant disorders, their common characteristics include:
❑early onset of malignant disease
❑increased incidence of bilateral cancer in paired organs (breasts, adrenal glands, kidneys, and eighth cranial nerve [acoustic neuroma])
❑increased incidence of multiple primary malignancies in nonpaired organs
❑abnormal chromosome complement in tumor cells.
Malignant melanoma:
Causes and incidence
(Professional Guide to Diseases (Eighth Edition))
Several factors seem to influence the development of melanoma:
❑Excessive exposure to sunlight — Melanoma is most common in sunny, warm areas and usually develops on parts of the body that are exposed to the sun.
❑ Skin type — Most persons who develop melanoma have blond or red hair, fair skin, and blue eyes; are prone to sunburn; and are of Celtic or Scandinavian ancestry. Melanoma is rare among Blacks; when it does develop, it usually arises in lightly pigmented areas (the palms, plantar surface of the feet, or mucous membranes).
❑ Hormonal factors — Pregnancy may increase risk and exacerbate growth.
❑ Family history — Melanoma is slightly more common within families.
❑ Past history of melanoma — A person who has had one melanoma is at greater risk of developing a second.
Melanoma is slightly more common in women than in men and is rare in children. Peak incidence occurs between ages 50 and 70, although the incidence in younger age-groups is increasing.
Lymphomas, malignant:
Causes
(Handbook of Diseases)
The cause of malignant lymphomas is unknown, although some theories suggest a viral source. Up to 35,000 new cases appear annually in the United States. Malignant lymphomas are two to three times more common in males than in females and occur in all age-groups.
Although rare in children, these lymphomas occur one to three times more often and cause twice as many deaths as Hodgkin’s disease in children under age 15. Incidence rises with age (median age is 50). Malignant lymphomas seem linked to certain races and ethnic groups, with increased incidence in whites and people of Jewish ancestry.
Bone tumors, primary malignant:
Causes
(Handbook of Diseases)
Although some cases of osteosarcoma are associated with genetic abnormalities (retinoblastoma, Rothmund Thomson syndrome) or exposure to carcinogens (such as ingested radium in watch dial painters), most cases have no immediately apparent cause. Ewing’s sarcoma cells demonstrate a characteristic translocation of genetic material from chromosome 22 to chromosome 11. Additional theories point to heredity, trauma, and excessive radiation therapy.
Brain tumors, malignant:
Causes
(Handbook of Diseases)
Some tumors are congenital, whereas others are hereditary. The cause of most brain tumors is unknown.
Malignant melanoma:
Causes
(Handbook of Diseases)
Several factors may influence the development of melanoma:
❑ Excessive exposure to ultraviolet light. Melanoma is most common in sunny, warm areas and commonly develops on parts of the body that are exposed to the sun. A person who has a blistering sunburn before age 20 has twice the risk of developing melanoma.
❑ Skin type. Most persons who develop melanoma have blond or red hair, fair skin, and blue eyes; are prone to sunburn; and are of Celtic or Scandinavian descent. Melanoma is rare among blacks; when it does develop, it usually arises in lightly pigmented areas (the palms, plantar surface of the feet, or mucous membranes).
❑ Autoimmune factors. Genetic and autoimmune effects may be causes.
❑ Hormonal factors. Pregnancy may increase risk and exacerbate growth.
❑ Family history. A person with a family history of melanoma has eight times the risk of developing the disorder.
❑ History of melanoma. A person who has had one melanoma has 10 times the risk of developing a second.
Benign tumor as a complication of other conditions:
Other conditions that might have Benign tumor as a complication may, potentially, be an underlying cause of Benign tumor. Our database lists the following as having Benign tumor as a complication of that condition:
Benign tumor as a symptom:
Conditions listing Benign tumor as a symptom may also be potential underlying causes of Benign tumor. Our database lists the following as having Benign tumor as a symptom of that condition:
- Carney syndrome
- Neurofibromatosis syndrome
- Neurofibromatosis syndrome Type II
- Scoliosis as part of NF
Related information on causes of Benign tumor:
As with all medical conditions, there may be many causal factors. Further relevant information on causes of Benign tumor may be found in:
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