| primary brain tumour | <neurology, oncology> May be subdivided into primary brain tumours and the more common, secondary brain tumours. Primary brain tumours (for example astrocytoma, craniopharyngioma, glioma, ependymoma, neuroglioma, oligodendroglioma, glioblastoma multiforme, meningioma, medulloblastoma) arise from the uncontrolled proliferation of cells within the brain. Secondary brain tumours occur from the spread of cancer into the brain from a distant cancerous organ (metastasis). Common symptoms of a brain tumour include headache, nausea, vomiting, seizures, change in mentation, neurologic symptoms and loss of memory. (06 Mar 1998) |
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| primary tumour | <oncology> The mass of tumour cells at the original site of the neoplastic event from the primary tumour metastasis will lead to the establishment of secondary tumours. (18 Nov 1997) |
| primitive neuroectodermal tumour | 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. (05 Mar 2000) |
| sand tumour | <tumour> A firm cellular neoplasm derived from fibrous tissue of the meninges, choroid plexus, and certain other structures associated with the brain, characterised by the formation of multiple, discrete, concentrically laminated, calcareous bodies (psammoma bodies); most of these neoplasms are histologically benign, but may lead to severe symptoms as a result of compressing the brain. Synonym: angiolithic sarcoma, sand tumour, Virchow's psammoma. (05 Mar 2000) |
| heterologous tumour | A tumour composed of a tissue unlike that from which it springs. (05 Mar 2000) |
| hilar cell tumour of ovary | A small benign masculinizing ovarian tumour derived from hilar cells, which resemble Leydig cells of the testis. (05 Mar 2000) |
| histoid tumour | Old term for a tumour composed of a single type of differentiated tissue. (05 Mar 2000) |
| secondary tumour | <oncology> A tumour that develops as a result of metastasis or spreads beyond the original cancer. (09 Oct 1997) |
| homologous tumour | <oncology> Any tumour which is composed of the same tissue as that in which it arose. (09 Oct 1997) |
| Hurthle cell tumour | A neoplasm of the thyroid gland composed of polyhedral acidophilic cells, thought by some to be oncocytes; it may be benign or malignant, the behaviour of the latter depending on the general microscopic pattern, whether follicular, papillary, or undifferentiated. See: Hurthle cell adenoma. Synonym: Hurthle cell carcinoma. (05 Mar 2000) |
| sertoli cell tumour | A rare benign tumour of the testis that histologically resembles the foetal testis. There are three varieties: diffuse stromal, mixed (stromal and epithelial), and tubular (epithelial). Sertoli cells in the epithelial elements may produce oestrogen and cause feminization. (12 Dec 1998) |
| sertoli-leydig cell tumour | An ovarian tumour usually of low-grade malignancy occurring most frequently in the third and fourth decades, with 75% seen in women under 40. It is rare, representing less than .02% of ovarian cancers. The tumour typically produces androgens with virilization being noted in 70-85% of the patients. (holland et al., cancer medicine, 3d ed, p1684) (12 Dec 1998) |
| sex cord-stromal tumour | A malignant neoplasm of the ovary or testis. These tumours differentiate toward sex cords (in embryonic gonads) in the form of female (i.e., granulosa and theca) cells, male (i.e., sertoli and leydig) cells, or indifferent elements. In the ovary, sex cord-stromal tumours comprise 5% of all ovarian neoplasms. In the testes, leydig and sertoli cell tumours comprise about 5% of all testicular neoplasms, 10% of which behave in a malignant fashion. (12 Dec 1998) |
| hylic tumour | <tumour> A neoplasm of pulp tissue, resulting from proliferation of elements derived from the embryonic pulp of epiblastic origin. Synonym: hylic tumour. Origin: G. Hyle, stuff, crude matter, + -oma, tumour (05 Mar 2000) |
| smooth muscle tumour | A tumour composed of smooth muscle tissue, as opposed to leiomyoma, a tumour derived from smooth muscle. (12 Dec 1998) |