tumor (tu´mor)

1. Any swelling or tumefaction. 2. neoplasm 3. One of the four signs of inflammation (t., calor, dolor, rubor) enunciated by Celsus. [L. tumor, a swelling]
acinar cell t. a solid and cystic t. of the pancreas, occurring in young women; t. cells contain zymogen granules.
acute splenic t. acute splenitis, enlargement, and softening of the spleen, usually due to bacteremia or severe bacterial toxemia.
adenoid t. adenoma, or neoplasm with glandlike spaces.
adenomatoid t. a small benign t. of the male epididymis and female genital tract, consisting of fibrous tissue or smooth muscle enclosing anastomosing glandlike spaces containing acid mucopolysaccharide lined by flattened cells that have ultra-structural characteristics of mesothelial cells.adenofibromyoma, adenoleiomyofibroma, angiomatoid t., benign mesothelioma of genital tract, Recklinghausen's t;
adenomatoid odontogenic t. a benign epithelial odontogenic t. appearing radiographically as a well-circumscribed radiolucent-radiopaque lesion usually surrounding the crown of an impacted tooth in an adolescent or young adult; characterized histologically by columnar cells organized in a duct-like configuration interspersed with spindle-shaped cells and amyloid-like deposition that gradually undergoes dystrophic calcification.adenoameloblastoma, ameloblastic adenomatoid t;
adipose t. lipoma
ameloblastic adenomatoid t. adenomatoid odontogenic t
amyloid t. nodular amyloidosis
angiomatoid t. adenomatoid t
aortic body t. chemodectoma
Bednar t. pigmented dermatofibrosarcoma protuberans
benign t. a t. that does not form metastases and does not invade and destroy adjacent normal tissue.innocent t;
blood t. term sometimes used to denote an aneurysm, hemorrhagic cyst, or hematoma.
borderline t. a neoplasm of the ovary, usually arising in young women, composed of complex epithelial hyperplasia without stromas invasion; may recur if incompletely removed surgically, but is clinically less aggressive than carcinoma.low malignant potential t;
Brenner t. a relatively infrequent benign neoplasm of the ovary, consisting chiefly of fibrous tissue that contains nests of cells resembling transitional type epithelium, as well as glandlike structures that contain mucin; origin is controversial, but it may arise from Walthard's cell rest; ordinarily found incidentally in ovaries removed for other reasons, especially in postmenopausal women.
Brooke's t. trichoepithelioma
brown t. a mass of fibrous tissue containing hemosiderin-pigmented macrophages and multinucleated giant cells, replacing and expanding part of a bone in primary hyperparathyroidism.
t. burden The total mass of tumor tissue carried by a patient with cancer.
Buschke-Löwenstein t. giant condyloma
calcifying epithelial odontogenic t. a benign epithelial odontogenic neoplasm derived from the stratum intermedium of the enamel organ; a painless, slowly growing, mixed radiolucent-radiopaque lesion characterized histologically by cords of polyhedral epithelial cells, deposits of amyloid, and spherical calcifications.Pindborg t;
carcinoid t. a usually small, slow-growing neoplasm composed of islands of rounded, oxyphilic, or spindle-shaped cells of medium size, with moderately small vesicular nuclei, and covered by intact mucosa with a yellow cut surface; neoplastic cells are frequently palisaded at the periphery of the small groups, and the latter have a tendency to infiltrate surrounding tissue. Such neoplasms occur anywhere in the gastrointestinal tract (and in the lungs and other sites), with approximately 90% in the appendix and the remainder chiefly in the ileum, but also in the stomach, other parts of the small intestine, the colon, and the rectum; those of the appendix and small t.'s seldom metastasize, but reported incidences of metatases from other primary sites and from t.'s exceeding 2.0 cm in diameter vary from 25 to 75%; lymph nodes in the abdomen and the liver may be conspicuously involved, but metastases above the diaphragm are rare. See also carcinoid syndrome.argentaffinoma;
carotid body t. chemodectoma
cellular t. a t. composed mainly of closely packed cells.
cerebellopontine angle t. acoustic schwannoma
chemoreceptor t. chemodectoma
chromaffin t. chromaffinoma
Codman's t. chondroblastoma of the proximal humerus.
collision t. two originally separate t.'s, especially a carcinoma and a sarcoma, that appear to have developed by chance in close proximity, so that an area of mingling exists. See also carcinosarcoma.
connective t. any t. of the connective tissue group, such as osteoma, fibroma, sarcoma.
dermal duct t. a benign small t. derived from the intradermal part of eccrine sweat gland ducts occurring often on the head and neck.
dermoid t. dermoid cyst
desmoid t. desmoid (2)
dysembryoplastic neuroepithelial t. a rare low grade neoplasm most frequently seen in children and associated with seizures and cortical dysplasia; the often multinodular, multicystic t. is comprised of an oligodendroglial-like background with accompanying neurons.
eighth nerve t. acoustic schwannoma
embryonal t. , embryonic t. a neoplasm, usually malignant, which arises during intrauterine or early postnatal development from an organ rudiment or immature tissue; it forms immature structures characteristic of the part from which it arises, and may form other tissues as well. The term includes neuroblastoma and Wilms' t., and is also used to include certain neoplasms presenting in later life, this usage being based on the belief that such t.'s arise from embryonic rests. See also teratoma.embryoma;
embryonal t. of ciliary body embryonal medulloepithelioma
endocervical sinus t. malignant germ cell t. commonly found in the ovary. The t. arises from primitive germ cells and develops into extra-embryonic tissue resembling the yolk sac.yolk sac carcinoma;
endodermal sinus t. a malignant neoplasm occurring in the gonads, in sacrococcygeal teratomas, and in the mediastinum; produces a-fetoprotein and is thought to be derived from primitive endodermal cells.yolk sac t;
endometrioid t. a t. of the ovary containing epithelial or stromal elements resembling t.'s of the endometrium.
Erdheim t. craniopharyngioma
Ewing's t. a malignant neoplasm which occurs usually before the age of 20 years, about twice as frequently in males, and in about 75% of patients involves bones of the extremities, including the shoulder girdle, with a predilection for the metaphysis; histologically, there are conspicuous foci of necrosis in association with irregular masses of small, regular, rounded, or ovoid cells (2 to 3 times the diameter of erythrocytes), with very scanty cytoplasm.endothelial myeloma, Ewing's sarcoma;
fecal t. coproma
fibroid t. old term for certain fibromas and leiomyomas.
giant cell t. of bone a soft, reddish brown, sometimes malignant, osteolytic t. composed of multinucleated giant cells and ovoid or spindle-shaped cells, occurring most frequently in an end of a long tubular bone of young adults.giant cell myeloma, osteoclastoma;
giant cell t. of tendon sheath a nodule, possibly inflammatory in nature, arising commonly from the flexor sheath of the fingers and thumb; composed of fibrous tissue, lipid- and hemosiderin-containing macrophages, and multinucleated giant cells.localized nodular tenosynovitis;
glomus t. [MIM*138000] an unusual vascular neoplasm composed of specialized pericytes (sometimes termed glomus cells), usually in single encapsulated nodular masses which may be several millimeters in diameter and occur almost exclusively in the skin; it is exquisitely tender and may be so painful that patients voluntarily immobilize an extremity, sometimes leading to atrophy of muscles; multiple glomus t.'s occur, sometimes with autosomal dominant inheritance. See also glomangioma.
glomus jugulare t. chemodectoma
Godwin t. benign lymphoepithelial lesion
granular cell t. a microscopically specific, generally benign t., often involving peripheral nerves in skin, mucosa, or connective tissue, derived from Schwann cells; the abundant cytoplasm contains lysosomal granules, the cells infiltrate between adjacent tissues although growth is slow, and adjacent surface epithelium may show hyperplasia.
granulosa cell t. a benign or malignant t. of the ovary arising from the membrana granulosa of the graafian follicle and frequently secreting estrogen; it is soft, solid, white or yellow, and consists of small round cells sometimes enclosing Call-Exner bodies; larger lipid-containing cells may be present.folliculoma (1);
Grawitz' t. old eponym for renal adenocarcinoma.
Gubler's t. a fusiform swelling on the wrist in lead palsy.
haarscheibe t. trichodiscoma [Ger. Haar, hair, + Scheibe, disk]
heterologous t. a t. composed of a tissue unlike that from which it springs.
hilar cell t. of ovary a small benign masculinizing ovarian t. derived from hilar cells, which resemble Leydig cells of the testis.
histoid t. old term for a t. composed of a single type of differentiated tissue.
homologous t. a t. composed of tissue of the same sort as that from which it springs.
Hürthle cell t. a neoplasm of the thyroid gland composed of polyhedral acidophilic cells, thought by some to be oncocytes; it may be benign or malignant, the behavior of the latter depending on the general microscopic pattern, whether follicular, papillary, or undifferentiated. See also Hürthle cell adenoma.Hürthle cell carcinoma;
hylic t. hyloma
innocent t. benign t
interstitial cell t. of testis Leydig cell adenoma
Koenen's t. periungual fibroma
Krukenberg's t. a metastatic carcinoma of the ovary, usually bilateral and secondary to a mucous carcinoma of the stomach, which contains signet-ring cells filled with mucus.
Landschutz t. a transplantable, possibly isoantigenic, highly virulent neoplasm which can be grown in any strain of mice; the host is killed in a few days by what is apparently an anaplastic carcinoma.
Lindau's t. hemangioblastoma
low malignant potential t. borderline t
malignant t. a t. that invades surrounding tissues, is usually capable of producing metastases, may recur after attempted removal, and is likely to cause death of the host unless adequately treated. See also cancer.
malignant mixed müllerian t. (MMMT) mixed mesodermal t
melanotic neuroectodermal t. of infancy a benign neoplasm of neuroectodermal origin that most often involves the anterior maxilla of infants in the first year of life. It presents clinically as a rapidly growing blue-black lesion producing a destructive radiolucency; histologically, it is characterized by small round undifferentiated t. cells interspersed with larger polyhedral melanin-producing cells arranged in an alveolar configuration.melanoameloblastoma, pigmented ameloblastoma, pigmented epulis, progonoma of jaw, retinal anlage t;
Merkel cell t. a rare malignant cutaneous t. seen in sun-exposed skin of elderly patients composed of dermal nodules of small round cells with scanty cytoplasm in a trabecular pattern; the tumor cells contain cytoplasmic dense core granules resembling neurosecretory granules seen in Merkel cells.primary neuroendocrine carcinoma of the skin, trabecular carcinoma;
mesonephroid t. mesonephroma
mixed t. a t. composed of two or more varieties of tissue.
mixed mesodermal t. a sarcoma of the body of the uterus arising in older women, composed of more than one mesenchymal tissue, especially including striated muscle cells.malignant mixed müllerian t;
mixed t. of salivary gland a t. composed of salivary gland epithelium and fibrous tissue with mucoid or cartilaginous areas.pleomorphic adenoma;
mixed t. of skin chondroid syringoma
mucoepidermoid t. mucoepidermoid carcinoma
Nelson t. a pituitary t. causing the symptoms of Nelson syndrome.
oil t. lipogranuloma
oncocytic hepatocellular t. fibrolamellar liver cell carcinoma
organoid t. a t. of complex structure, glandular in origin, containing epithelium, connective tissue, etc.
Pancoast t. an adenocarcinoma of a lung apex causing Pancoast syndrome.superior pulmonary sulcus t;
papillary t. papilloma
paraffin t. paraffinoma
pearl t. obsolete term for cholesteatoma.
phantom t. accumulation of fluid in the interlobar spaces of the lung, secondary to congestive heart failure, radiologically simulating a neoplasm.
phyllodes t. a spectrum of neoplasms consisting of a mixture of benign epithelium and stroma with variable cellularity and cytologic abnormalities, ranging from benign phyllodes t. to cytosarcoma phyllodes; most often involves the breast.
pilar t. of scalp a solitary t. of the scalp in elderly women that may ulcerate; microscopically resembles squamous cell carcinoma composed of glycogen-rich clear cells, but is benign.proliferating tricholemmal cyst;
Pindborg t. calcifying epithelial odontogenic t
Pinkus t. fibroepithelioma
placental site trophoblastic t. a t. usually arising in the uterus of parous women during reproductive years. Histologically, the t. consists of a predominance of intermediate trophoblastic cells with fibrinoid material and vascular invasion.
pontine angle t. a t. in the angle formed by the cerebellum and the lateral pons, often refers to an acoustic schwannoma.
potato t. of neck a firm nodular mass in the neck, usually a carotid body t. (chemodectoma).
Pott's puffy t. a circumscribed swelling of the scalp indicating an underlying osteitis of the skull or an extradural abscess.
pregnancy t. granuloma gravidarum
primitive neuroectodermal t. a designation used to refer to a group of morphologically similar embryonal neoplasms that arise in intracranial and peripheral sites of the nervous system and which may show various degrees of cellular differentiation; includes medulloblastoma, pineoblastoma, etc.
ranine t. ranula (2)
Rathke's pouch t. craniopharyngioma
Recklinghausen's t. adenomatoid t
retinal anlage t. melanotic neuroectodermal t. of infancy
Rous t. Rous sarcoma
sand t. psammomatous meningioma
Sertoli cell t. androblastoma (1)
solitary fibrous t. a benign t. of fibrous tissue which usually arises in the pleural space on other sites.benign mesothelioma;
squamous odontogenic t. a benign epithelial odontogenic t. thought to arise from the epithelial cell rests of Malassez; appears clinically as a radiolucent lesion closely associated with the tooth root and histologically as islands of squamous epithelium enclosed by a peripheral layer of flattened cells.
sugar t. a benign clear cell t. of the lung containing abundant glycogen.
superior pulmonary sulcus t. Pancoast t
teratoid t. teratoma
theca cell t. thecoma
transmissible venereal t. canine venereal granuloma
triton t. a peripheral nerve t. with striated muscle differentiation, seen most often in neurofibromatosis; named after Masson's theory of transformation of motor nerve fibers into muscle in triton salamanders.
turban t. cylindroma of the scalp which, when overgrown, may resemble a turban.
villous t. villous papilloma
Warthin's t. adenolymphoma
Wilms' t. a malignant renal t. of young children, composed of small spindle cells and various other types of tissue, including tubules and, in some cases, structures resembling fetal glomeruli, and striated muscle and cartilage. Often inherited as an autosomal dominant trait [MIM*194070, *194080, *194090].adenomyosarcoma, embryoma of the kidney, nephroblastoma;
wing-beating t. a coarse, irregular t. that is most prominent when the limbs are held outstretched, reminiscent of a bird flapping its wings; due to up and down excursion of arm at abducted shoulder. Seen mainly with Wilson's disease.
Yaba t. a poxvirus-induced neoplasm of monkeys caused by the Yaba monkey virus, a member of the family Poxviridae; tumor-like growths occur chiefly on the head and limbs; the natural disease has been reported only in Africa in monkeys kept outdoors.
yolk sac t. endodermal sinus t
Zollinger-Ellison t. a non-beta cell t. of pancreatic islets causing the Zollinger-Ellison syndrome.


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