| pineal tumours | <radiology> SIGNS: aqueductal obstruction most likely to be hydrocephalus, paralysis of upward gaze (due to pressure on quarigeminal plate), precocious puberty, symptoms of hypothalamic, thalamic, cerebellar or pyramidal lesion TYPES: germ-cell (teratoid) tumours, teratoma, germinoma / atypical teratoma, endodermal sinus (yolk sac) tumour, choriocarcinoma, pineal-cell tumours, pineocytoma, pineo---, others, glioma, ganglioneuroma, ganglioglioma (12 Dec 1998) |
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| plant tumours | A localised proliferation of plant tissue forming a swelling or outgrowth, commonly with a characteristic shape and unlike any organ of the normal plant. Plant tumours or galls usually form in response to the action of a pathogen or a pest. (12 Dec 1998) |
| posterior fossa tumours | <radiology> Midline, medulloblastoma (hyperdense, enhances), astrocytoma (hypodense, enhances), 4th ventricle, ependymoma (most common, slow-growing, expands ventricle), medulloblastoma (usually obliterates ventricular cavity), choroid plexus papilloma (more common in lateral ventricles) (12 Dec 1998) |
| primitive neuroectodermal tumours | A type of brain tumour. Prenatal diagnosis: diagnosis before birth. Methods for prenatal diagnosis include ultrasound (of the uterus, placenta and developing foetus), chorionic villus sampling to obtain tissue for chromosome or biochemical analysis, amniocentesis to obtain amniotic fluid for the analysis of chromosmes, enzymes, DNA, etc. A growing number of birth defects and diseases are now amenable to prenatal diagnosis. Also called antenatal diagnosis. (12 Dec 1998) |
| nerve sheath tumours | Tumours arising in the sheath surrounding the axon of some nerve cells and formed by the plasma membrane of schwann cells in the peripheral nervous sytem and by oligodendrocytes in the central nervous system. Neurofibromas and neurilemmomas are the most commonly occurring tumours of this type. (12 Dec 1998) |
| neuroectodermal tumours | Malignant neoplasms arising in the neuroectoderm, the portion of the ectoderm of the early embryo that gives rise to the central and peripheral nervous systems, including some glial cells. (12 Dec 1998) |
| neuroendocrine tumours | Tumours whose cells possess secretory granules and originate from the neuroectoderm, i.e., the cells of the ectoblast or epiblast that program the neuroendocrine system. Common properties across most neuroendocrine tumours include ectopic hormone production (often via apud cells), the presence of tumour-associated antigens, and isozyme composition. (12 Dec 1998) |
| desmoplastic tumours | <radiology> Carcinoid of small bowel or colon, Hodgkin's lymphoma, scirrhous gastric carcinoma (12 Dec 1998) |
| developmental brain tumours | <radiology> 1% of all brain tumours, germ-cell tumours, epidermoid more than dermoid more than > Teratoma, usually midline, craniopharyngioma, colloid cyst, lipoma, hamartoma (12 Dec 1998) |
| duodenal tumours | <radiology> 90% benign, in 2nd and 3rd portion: 50% malignant, in 4th portion: most malignant, of malignancies: 80-90% leading to adenocarcinoma Differential diagnosis: benign, tubular adenoma, leiomyoma, lipoma, hamartoma (Peutz-Jeghers), prolapsed antral polyp, Brunner's gland adenoma (really hypertrophy and hyperplasia), malignant, adenocarcinoma (80-90% of malignant lesions), villous adenoma (pre-malignant), carcinoid / isleT-cell tumour (12 Dec 1998) |
| infantile brain tumours | <radiology> Can be present at birth: choroid plexus papilloma, medulloblastoma, craniopharyngioma, ependymoma, astrocytoma, teratoma (12 Dec 1998) |
| odontogenic tumours | Neoplasms produced from tooth-forming tissues. (12 Dec 1998) |
| lymphatic vessel tumours | Neoplasms composed of lymphoid tissue, a lattice work of reticular tissue the interspaces of which contain lymphocytes. The concept does not refer to neoplasms located in lymphatic vessels. (12 Dec 1998) |
| anovular ovarian follicle | A follicle that does not contain an ovum. (05 Mar 2000) |
| atretic ovarian follicle | A follicle that degenerates before coming to maturity; great numbers of such atretic follicle's occur in the ovary before puberty; in the sexually mature woman, several are formed each month. Synonym: corpus atreticum. (05 Mar 2000) |