swelling or morbid enlargement; this is one of the cardinal signs of inflammation
a new growth of tissue in which cell multiplication is uncontrolled and progressive. Tumors are also called neoplasms
, which means that they are composed of new and actively growing tissue. Their growth is faster than that of normal tissue, continuing after cessation of the stimuli that evoked the growth, and serving no useful physiologic purpose. adj., adj
Tumors are classified in a number of ways, one of the simplest being according to their origin and whether they are malignant or benign. Tumors of mesenchymal origin include fibroelastic tumors and those of bone, fat, blood vessels, and lymphoid tissue; they may be benign or malignant (sarcoma
). Tumors of epithelial origin are found in glandular tissue and such organs as the breast, stomach, uterus, or skin; they also may be either benign or malignant (carcinoma
). Mixed tumors contain different types of cells derived from the same primary germ layer, and teratomas
contain cells derived from more than one germ layer; both kinds may be benign or malignant.
. Benign tumors do not endanger life unless they interfere with normal functions of other organs or affect a vital organ. They grow slowly, pushing aside normal tissue but not invading it. They are usually encapsulated, well demarcated growths. They are not metastatic; that is, they do not form secondary tumors in other organs. Benign tumors usually respond favorably to surgical treatment and some forms of radiation therapy
. These tumors are composed of embryonic, primitive, or poorly differentiated cells. They grow in a disorganized manner and so rapidly that nutrition of the cells becomes a problem. For this reason necrosis and ulceration are characteristic of malignant tumors. They also invade surrounding tissues and are metastatic, initiating the growth of similar tumors in distant organs. (See also cancer
Gross appearance of benign (A) and malignant (B) tumors. From Damjanov, 2000.
bladder tumor a tumor of the urinary bladder; see also bladder cancer.
brown tumor a giant-cell granuloma produced in and replacing bone, occurring in osteitis fibrosa cystica and due to hyperparathyroidism.
a slow-growing mass of warts found usually in the prepuce but sometimes elsewhere in the perianal region; it starts as a plaque and may grow into a large cauliflowerlike mass. Called also giant condyloma
carotid body tumor
of a carotid body
, found as a firm round mass at the bifurcation of the common carotid artery.
connective tissue tumor
any tumor arising from a connective tissue structure, such as a fibroma
giant cell tumor
2. a bone tumor, ranging from benign to frankly malignant, composed of cellular spindle cell stroma containing multinucleated giant cells resembling osteoclasts.
3. a small yellow benign tumorlike nodule of tendon sheath origin, usually of the wrist and fingers or ankle and toes, laden with lipophages and containing multinucleated giant cells.
glomus tumor 1.
a blue-red, extremely painful chemodectoma
involving an arteriovenous anastomosis or cluster of blood cells, which may be found anywhere in the skin, most often in the distal portion of the fingers and toes, especially beneath the nail. Such tumors may also occur in the stomach and nasal cavity.
granular cell tumor a relatively common neoplasm whose cells have a granular appearance by light microscopy; it is usually benign but occasionally malignant, and multiple tumors may occur. It can be found anywhere but is most often seen in the oral cavity, especially in the tongue.
heterologous tumor one made up of tissue differing from that in which it grows.
homoiotypic tumor (homologous tumor) one made up of tissue resembling that in which it grows.
lipoid cell tumor of ovary
a usually benign ovarian tumor composed of eosinophilic cells or cells with lipoid vacuoles; it causes masculinization
tumor lysis syndrome severe hyperphosphatemia, hyperkalemia, hyperuricemia, and hypocalcemia occurring after effective induction chemotherapy of rapidly growing malignant neoplasms; thought to be due to release of intracellular products after cell lysis.
melanotic neuroectodermal tumor
a benign, rapidly growing, dark tumor of the jaw or occasionally some other site, almost always seen in infants; called also melanoameloblastoma
mixed tumor one composed of more than one type of neoplastic tissue.
peripheral neuroectodermal tumor (PNET) any of a heterogeneous group of neoplasms originating in supporting structures or neuronal tissue, primarily of the extremities, pelvis, or chest wall; seen most often in adolescents and young adults and frequently having widespread metastases.
plasma cell tumor
1. plasma cell dyscrasias.
theca cell tumor a fibroidlike tumor of the ovary containing yellow areas of fatty material derived from theca cells.
of the scalp that are grouped together so as to cover the entire scalp.
a rapidly developing malignant mixed tumor of the kidneys, made up of embryonal elements, occurring chiefly in children before the seventh year; a genetic component is suspected in its etiology. It may be accompanied by congenital defects such as urinary tract abnormalities, absent iris of the eye, and asymmetry of parts. With treatment, the prognosis is excellent. Called also embryonal carcinosarcoma
yolk sac tumor
a malignant germ cell tumor
of children that represents a proliferation of both yolk sac
endoderm and extraembryonic mesenchyme
. It produces α-fetoprotein
and most often occurs in the testes, but is also seen in the ovaries and some extragonadal sites. Called also endodermal sinus tumor
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.
tumor (too'mor) [L. tumor, a swelling]
1. A swelling or enlargement; one of the four classic signs of inflammation.
An abnormal mass. Growth or proliferation that is independent of neighboring tissues is a hallmark of all tumors, benign and malignant. Synonym: neoplasm
adenomatoid odontogenic tumorAdenoameloblastoma.
An inexact term to describe any intracranial mass: neoplastic, cystic, inflammatory (abscess), or syphilitic.
Neoplastic brain tumors may be benign or malignant. Malignant brain lesions may be primary or secondary, resulting from metastatic spread of other cancers. Primary malignant brain tumors make up from 10% to 30% of adult cancers and about 20% in children, but any of these tumors may occur at any age. Incidence in children is usually greatest before age 12, with astrocytomas, medulloblastomas, ependymomas, and brain stem gliomas being most common. In adults the most common tumors are gliomas and meningiomas, usually occurring supratentorially. Other malignant tumor types are oligodendrogliomas and acoustic neuromas (Schwannomas). Most malignant brain tumors are metastatic, with 20% to 40% of patients with cancer developing brain metastasis. The cause of primary brain cancers is unknown; however, one known environmental risk is exposure to ionizing radiation. Cell phone use has been implicated in acoustic neuromas. Central nervous system changes occur as the lesions invade and destroy tissue, and, because the tumors compress the brain, cranial nerves, and cerebral blood vessels, the compression causes cerebral edema and increased intracranial pressure (ICP). Most clinical signs are due to the increased ICP, but signs and symptoms may vary due to the type of tumor, its location, and the degree and speed of invasion. Usually the onset of symptoms is insidious, with brain tumors frequently misdiagnosed.
The patient is evaluated for neurological deficits (headache, mental activity changes, behavioral changes, weakness, sensory losses, or disturbances of vision, speech, gait, or balance). The patient is monitored for seizures and increased ICP. Diagnostic tools include skull x-rays, brain scan, CT scan, MRI, cerebral angiography, and EEG. Lumbar puncture demonstrates increased pressure and protein levels, decreased glucose levels, and (sometimes) tumor cells in the cerebrospinal fluid (CSF). Definitive diagnosis is by tissue biopsy performed by stereotactic surgery.
Treatment includes excision if the tumor is resectable, and size reduction if he tumor is not respectable; relieving cerebral edema, reducing ICP, and managing other symptoms; and preventing further neurologic damage. Treatment is determined by the tumor’s histology, radiosensitivity, and location. Functional MRI can map the brain function surrounding a tumor to help design a surgical approach that removes the tumor while avoiding damage to areas critical for normal functioning. Surgery, radiation, chemotherapy, and/or decompression for increased ICP with diuretics, corticosteroids, or sometimes ventroatrial or ventroperitoneal CSF shunting. Focused and computerized robotic radiation methods such as the Gamma Knife and Cyberknife permit delivery of more radiation to the tumor and less to surrounding normal tissue.
Radiation therapy can cause inflammation; therefore the patient is monitored for increasing ICP. If radiation is to be used after surgery, it will be delayed until the surgical wound has healed. However, even after local healing occurs, radiation can break down the wound; therefore the area of the incision must be assessed for infection and sinus formation. Chemotherapy for malignant brain tumors includes use of nitrosureas (BCNU, CCNU, procarbazine) to help break down the blood-brain barrier allowing entrance of other chemotherapy agents. Antiemetics are provided before and after chemotherapy to minimize nausea and prevent vomiting. The patient is assessed over the following weeks for bone marrow suppression, is advised to report signs of infection or bleeding, and is to avoid contact with crowds and people with respiratory infections. The oral agent temozolomide (Temodar) crosses the blood-brain barrier and is usually well tolerated by the patient. Intrathecal or intra-arterial administration helps increase drug action. Convection-enhanced delivery systems infuse the antitumor agent directly into the brain, bypassing the blood-brain barrier, to pump drugs slowly through 2 to 4 implanted catheters to where a tumor was removed, to attach to and kill remaining tumor cells, and to shrink a tumor before surgery. A disc-shaped drug wafer can be implanted during surgery to deliver chemotherapy directly to the tumor. MRI spectroscopy reveals the physiology of treated tumors to differentiate dead tissue from an actively growing tumor. The patient must be monitored closely for changes in neurologic status and increases in ICP. A patent airway must be maintained and respiratory changes monitored. The patient's safety must be ensured. Temperature must be monitored closely. Steroids and osmotic diuretics are administered as prescribed. Fluid intake may be restricted to 1500 ml/24 hr. Fluid and electrolyte balance is monitored to prevent dehydration. Stress ulcers may occur; therefore the patient is assessed for abdominal distention, pain, vomiting, and tarry stools. Stools are tested for occult blood. Antacids and anti-histamine-2 agents are administered as prescribed.
For postcraniotomy surgery, all general patient care concerns apply. General neurologic status and ICP remain the assessment priorities. Positioning of the patient after surgery depends on the procedure: after supratentorial craniotomy, the head of the bed should be elevated 30° and the patient positioned on the side to promote venous drainage, reduce cerebral edema, allow drainage of secretions and prevent aspiration. After infratentorial craniotomy, the patient should be kept flat for 48 hr but log-rolled side to side every 2 hr to minimize complications from immobility. Because brain tumors and their treatment frequently result in residual disabling neurologic deficits, a rehabilitation program should be started early. Physical and occupational therapists help the patient maintain independence and quality of life and provide aids for self-care and mobility. If the patient is aphasic or develops dysphagia, a speech pathologist must be consulted. Depression is common, and psychological consultation for behavioral or drug therapies may be helpful.
Emotional support is provided to the patient and family for treatments, disabilities, changes in lifestyle, and end-of-life issues. The patient and family are referred to resource and support services (e.g., social service, home health care agencies, the American Cancer Society, and other such voluntary agencies).
Brenner tumor See: Brenner tumor
A benign fibrotic mass found within the bone of patients with unchecked hyperparathyroidism. The tumor appears brown on gross examination because it contains blood and by-products of the metabolism of hemoglobin.
A giant condyloma acuminatum, typically found on the genitals or anus, caused by infection with papilloma virus. In men, it is almost always found under the foreskin (it is rarely reported in circumcised men). It may transform into a verrucous carcinoma and cause deep local tissue invasion.
calcifying epithelial odontogenic tumorPindborg tumor.
carotid body tumor
A benign tumor of the carotid body.
1. A malignant growth made up of two or more different cell types occurring simultaneously in the same location.
2. A cancerous growth made up of two or more malignancies that have metastasized toward each other.
connective tissue tumor
Any tumor of connective tissue such as fibroma, lipoma, chondroma, or sarcoma.
A painful, nodular mass in the large bowel, a result of infection with Oesophagostomum bifurcum, a West African worm.
A tumor of fibrous connective tissue. Synonym: desmoma
dysembryoplastic neuroepithelial tumor Abbreviation: DNET
A benign mass of misshapen brain cells. DNETs are a relatively rare cause of seizures in children and adolescents.
A pituitary adenoma that does not secrete a clinically important concentration of hormones. Endocrine-inactive tumors were formerly known as chromophobe adenomas. They are the most commonly detected neoplasms of the pituitary gland.
A tumor composed of erectile tissue.
Ewing tumor See: Ewing tumor
An enlargement due to hemorrhage into tissue or extravasation of fluid into a space, rather than cancer.
fibroid tumorUterine leiomyoma.
follicular tumorAn epidermoid cyst.
A tumor that is able to synthesize the same product as the normal tissues from which it arises, esp. an endocrine or nonendocrine tumor that produces hormones.
giant cell tumor
1. A malignant or benign bone tumor that probably arises from connective tissue of the bone marrow. Histologically, it contains a vascular reticulum of stromal cells and multinucleated giant cells.
2. A yellow giant cell tumor of a tendon sheath.
4. A chondroblastoma.
giant cell tumor of bone
A benign or malignant tumor of bone in which the cells are multinucleated and surrounded by cellular spindle cell stroma.
giant cell tumor of tendon sheath
A localized nodular tenosynovitis.
granulosa cell tumor
A malignant tumor that arises from the supporting cells (stromal cells) that encircle the ovary. Many of these cells produce estrogen; those that do can cause breast tenderness, endometrial hyperplasia, menorrhagia, or, in children, sexual precocity.
granulosa-theca cell tumor
An estrogen-secreting tumor of the ovary made up of either granulosa or theca cells.
Gubler tumor See: Gubler, Adolphe
A tumor in which the tissue differs from that in which it is growing.
A tumor in which the tissue resembles that in which it is growing.
Hürthle cell tumor See: Hürthle, Karl W.
hilus cell tumor
A rare, steroid-hormone–producing tumor of the ovary. It is an occasional cause of virilization.
islet cell tumor
A tumor of the islets of Langerhans of the pancreas.
Klatskin tumor See: Klatskin tumor
Krukenberg tumor See: Krukenberg, Friedrich Ernst
lipoid cell tumor of the ovary
A masculinizing tumor of the ovary. It may be malignant.
mast cell tumor
A benign nodular accumulation of mast cells.
melanotic neuroectodermal tumor
A benign tumor of the jaw, occurring mostly during the first year of life.
mesenchymal mixed tumor
A tumor composed of tissue that resembles mesenchymal cells.
A colloquial term for a galactocele. Synonym: galactocele (1) See: caked breast
Pancoast tumor See: Pancoast tumor
A neoplasm composed of or resembling enlarged papillae. See: papilloma
1. An apparent tumor due to muscular contractions or flatus that resolves on reexamination of the patient.
2. A mass that resembles a tumor in only one view of a chest x-ray film. On other views it either disappears or appears to be an encapsulated fluid collection.
placental site trophoblastic tumor Abbreviation: PSTT
A rare form of gestational trophoblastic disease simulating carcinoma and arising at the attachment of the placenta to the uterine wall.
Pindborg tumor See: Pindborg tumor
In a patient with metastatic cancer, the lesion assumed to be the source of the metastases.
primitive neuroectodermal tumor Abbreviation: PNET
Recklinghausen tumor See: Recklinghausen, Friedrich D. von
A tumor that has formed at a location remote from the original location of the tumor. Generally, a secondary tumor results from the spread of malignant cells through the lymphatic system or bloodstream.
A tumor of embryonic remains from all germinal layers. See: teratoma
Multiple cutaneous cylindromata that cover the scalp like a turban.
uterine tumor, tumor of the uterus
Warthin tumor See: Warthin tumor
Wilms tumor See: Wilms tumor
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