| theca cell tumour | A sex cord-stromal tumour of the postmenopausal ovary that is yellow, large, and unilateral, composed of fascicles of lipid-rich spindle cells interspersed with collagen, reticulin fibres, and hyaline plaques. Thecomas and other oestrogen-producing tumours (e.g., granulosa cell tumours) may induce adenomatous hyperplasia of the endometrium or well-differentiated endometrial carcinoma in 3%-20% of the cases. (12 Dec 1998) |
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| ear tumour | A disorder where there are noncancerous lumps or growths within the ear canal or on the pinna of the ear (external ear). most lumps are sebaceous cysts but some are bony overgrowths known as exostoses (or osteomas). If large enough they may interfere with hearing. In this case surgical removal may be required. (27 Sep 1997) |
| eighth nerve tumour | <tumour> A benign neoplasm of the intracranial segment of the eighth cranial nerve, producing cerebellar, lower cranial nerve, and brainstem signs and symptoms. Synonym: acoustic neuroma, cerebellopontine angle tumour, eighth nerve tumour. (05 Mar 2000) |
| embryonal tumour | Embryonic tumour, 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' tumour, and is also used to include certain neoplasms presenting in later life, this usage being based on the belief that such tumours arise from embryonic rests. See: teratoma. Synonym: embryoma. (05 Mar 2000) |
| embryonal tumour of ciliary body | <tumour> An epitheliomatous tumour of the nonpigmented layer of the ciliary epithelium. Synonym: embryonal tumour of ciliary body. (05 Mar 2000) |
| endocervical sinus tumour | Malignant germ cell tumour commonly found in the ovary. The tumour arises from primitive germ cells and develops into extra-embryonic tissue resembling the yolk sac. Synonym: yolk sac carcinoma. (05 Mar 2000) |
| endodermal sinus tumour | An unusual and aggressive tumour of germ-cell origin that reproduces the extraembryonic structures of the early embryo. It is the most common malignant germ cell tumour found in children. It is characterised by a labyrinthine glandular pattern of flat epithelial cells and rounded papillary processes with a central capillary (schiller-duval body). The tumour is rarely bilateral. Before the use of combination chemotherapy, the tumour was almost invariably fatal. (12 Dec 1998) |
| endometrioid tumour | A tumour of the ovary containing epithelial or stromal elements resembling tumour's of the endometrium. (05 Mar 2000) |
| transmissible venereal tumour | A rapidly growing, soft, easily bleeding, infectious, connective tissue tumour occurring in the vagina of the female dog and on the penis and sheath of the male; ordinarily transmitted by coitus. Synonym: transmissible venereal tumour. (05 Mar 2000) |
| triton tumour | A peripheral nerve tumour with striated muscle differentiation, seen most often in neurofibromatosis; named after Masson's theory of transformation of motor nerve fibres into muscle in triton salamanders. (05 Mar 2000) |
| Erdheim tumour | <oncology, tumour> A form of primary brain tumour which develops in the pituitary gland. These tumours often secrete increased quantities of pituitary hormones (for example growth hormone) which can result in conditions such as gigantism and acromegaly. They are often benign and rare and comprise less than 5% of childhood brain tumours. Other symptoms include vision changes, headache and weight gain. Treatment often includes a combination of surgery and radiation therapy. (27 Sep 1997) |
| trophoblastic tumour | <oncology, tumour> A malignant and rapidly growing tumour which arises from foetal tissue. The preceding factor is a hydatidiform mole. Symptoms include continued vaginal bleeding in a women with a recent history of hydatidiform mole, abortion or term pregnancy. (27 Sep 1997) |
| trophoblastic tumour, placental site | A tumour that arises from the trophoblast of the placental bed and is composed mainly of cytotrophoblastic cells. It encompasses lesions of low- and high-grade malignancy. (holland et al., cancer medicine, 3d ed, p1691) (12 Dec 1998) |
| tumour | 1. <oncology> An abnormal mass of tissue that results from excessive cell division that is uncontrolled and progressive, also called a neoplasm. Tumours perform no useful body function. They may be either benign (not cancerous) or malignant. 2. Swelling, one of the cardinal signs of inflammations, morbid enlargement. Origin: L. Tumere = to swell (12 May 1997) |
| tumour angiogenesis factor | <growth factor> Substance released from a tumour that promotes vascularisation of the mass of neoplastic cells. Once a tumour becomes vascularised, it will grow more rapidly and is more likely to metastasise. TAF is almost certainly more than one substance. See: angiogenin. (18 Nov 1997) |