A tumor is a growth — a mass of tissue — that has no function. Tumors can be harmless (benign) or harmful (malignant), but they are never any fun.

When a bunch of cells form a new growth in or on an animal, and those cells have no purpose, the result is a tumor. The word tumor comes directly from Latin word for “swelling.” Tumors can be big or small, harmless or harmful. Benign tumors are not a cause for concern, but a malignant tumor is serious and could be cancerous. A doctor must test a tumor to see which kind it is.

Definitions of tumor

n an abnormal new mass of tissue that serves no purpose

neoplasm, tumour
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acanthoma, skin tumor
a neoplasm originating in the epidermis
a tumor consisting of a mass of blood or lymphatic vessels
benign tumor, benign tumour, nonmalignant neoplasm, nonmalignant tumor, nonmalignant tumour
a tumor that is not cancerous
blastocytoma, blastoma, embryonal carcinosarcoma
a tumor composed of immature undifferentiated cells
brain tumor, brain tumour
a tumor in the brain
a small tumor (benign or malignant) arising from the mucosa of the gastrointestinal tract; usually associated with excessive secretion of serotonin
an abdominal tumor
a tumor composed of granulation tissue resulting from injury or inflammation or infection
adipose tumor, lipoma
a tumor consisting of fatty tissue
malignant neoplasm, malignant tumor, metastatic tumor
a tumor that is malignant and tends to spread to other parts of the body
a tumor arising in the meninges which surround the brain and spinal cord; usually slow growing and sometimes malignant
neurilemoma, neurofibroma
tumor of the fibrous covering of a peripheral nerve
any tumor derived from cells of the nervous system
phaeochromocytoma, pheochromocytoma
a vascular tumor of the adrenal gland; hypersecretion of epinephrine results in intermittent or sustained hypertension
tumor of the pineal gland
neoplasm of plasma cells (usually in bone marrow)
psammoma, sand tumor
a tumor derived from fibrous tissue of the meninges or choroid plexus or certain other structures associated with the brain; characterized by sandlike particles
a tumor consisting of a mixture of tissues not normally found at that site
a benign epithelial tumor of glandular origin
a common benign tumor of cartilage cells
glioblastoma, spongioblastoma
a fast-growing malignant brain tumor composed of spongioblasts; nearly always fatal
a tumor of the brain consisting of neuroglia
a malignant neoplasm composed of carcinoma and sarcoma extensively intermixed
benign slow-growing tumor of cartilaginous cells at the ends of tubular bones (especially in the hands and feet)
nonmalignant tumor of connective tissue
a small rubbery granuloma that is characteristic of an advanced stage of syphilis
skin tumor that grows rapidly (especially in older people) and resembles a carcinoma but does not spread; it usually disappears spontaneously, often leaving a scar
cancer, malignant neoplastic disease
any malignant growth or tumor caused by abnormal and uncontrolled cell division; it may spread to other parts of the body through the lymphatic system or the blood stream
a rare malignant neoplasm arising from vascular tissue; usually occurs in the breast and skin and is believed to originate from the endothelial cells of blood vessels
haemangioma, hemangioma
benign angioma consisting of a mass of blood vessels; some appear as birthmarks
benign angioma consisting of a mass of lymphatic vessels
spider angioma, spider nevus, vascular spider
a dilation of superficial capillaries with a central red dot from which blood vessels radiate
a tumor of the bone marrow (usually malignant) composed of cells normally found in bone marrow
a benign tumor composed of muscle tissue
a benign tumor of connective tissue containing jellylike material
tumor (usually benign) of the sheath surrounding a nerve
malignant tumor containing embryonic nerve cells; usually metastasizes quickly
malignant tumor of the neuroepithelium
benign tumor of bone and fibrous tissue; occurs in the vertebrae or femur or tibia or arm bones (especially in young adults)
benign tumor containing both bone and cartilage; usually occurs near the end of a long bone
a slow growing benign tumor of consisting of bone tissue; usually on the skull or mandible
papillary tumor, papillary tumour, papilloma, villoma
a benign epithelial tumor forming a rounded mass
malignant ocular tumor of retinal cells; usually occurs before the third year of life; composed of primitive small round retinal cells
Type of:
(pathology) an abnormal proliferation of tissue (as in a tumor)

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