| giant cell tumour | <radiology> Osteoclastoma, GCT, any age, typically 20-35, site: metaphysis into epiphysis, 50% at knee (distal femur, proximal tibia), long bones, patella, spine, eccentric, expansile, with or without soap bubble appearance, treatment: curette, fill with methacrylate, 10% recur, a few are premalignant or malignant, cannot determine malignancy by XR (12 Dec 1998) |
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| giant cell tumour of bone | A bone tumour composed of cellular spindle-cell stroma containing scattered multinucleated giant cells resembling osteoclasts. The tumours range from benign to frankly malignant lesions. The tumour occurs most frequently in an end of a long tubular bone in young adults. (12 Dec 1998) |
| giant cell tumour 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 haemosiderin-containing macrophages, and multinucleated giant cells. Synonym: localised nodular tenosynovitis. (05 Mar 2000) |
| giant cell tumours | Tumours of bone tissue or synovial or other soft tissue characterised by the presence of giant cells. The most common are giant cell tumour of tendon sheath and giant cell tumour of bone. (12 Dec 1998) |
| giant cells, foreign-body | Multinucleated cells (fused macrophages), characteristic of granulomatous inflammation, which form around exogenous material in the skin. They are similar in appearance to langhans giant cells (giant cells, langhans), but foreign-body giant cells have more abundant chromatin and their nuclei are scattered in an irregular pattern in the cytoplasm. (12 Dec 1998) |
| giant cells, langhans | Multinucleated cells (fused macrophages) seen in granulomatous inflammations such as tuberculosis, syphilis, sarcoidosis, and deep fungal infections. They resemble foreign-body giant cells (giant cells, foreign body) but langhans giant cells contain less chromatin and their nuclei are arranged peripherally in a horseshoe-shaped pattern. Langhans giant cells occur frequently in delayed hypersensitivity. (12 Dec 1998) |
| giant chromosome | <cell biology> Giant chromosomes produced by the successive replication of homologous pairs of chromosomes, joined together (synapsed) without chromosome separation or nuclear division. They thus consist of many up to 1000) identical chromosomes (strictly chromatids) running parallel and in strict register. The chromosomes remain visible during interphase and are found in some ciliates, ovule cells in angiosperms and in larval Dipteran tissue. The best known polytene chromosomes are those of the salivary gland of the larvae of Drosophila melanogaster which appear as a series of dense bands interspersed by light interbands, in a pattern characteristic for each chromosome. The bands, of which there are about 5,000 in Drosophila melanogaster, contain most of the DNA (ca 95%) of the chromosomes and each band roughly represents one gene. The banding pattern of polytene chromosomes provides a visible map to compare with the linkage map determined by genetic studies. Some segments of polytene chromosome show chromosome puffs, areas of high transcription. (18 Nov 1997) |
| giant colon | An abnormally large or dilated colon, the condition may be congenital or acquired, acute or chronic. (18 Nov 1997) |
| giant condyloma | A large type of condyloma acuminatum found in the anus, vulva, or preputial sac of the penis of middle-aged, uncircumcised men; it tends to extend deeply and recur. Synonym: Buschke-Lowenstein tumour. (05 Mar 2000) |
| giant drusen | An obsolete term for a glial hamartoma of the optic nerve head or the peripapillary retina, seen in tuberous sclerosis. (05 Mar 2000) |
| giant follicular lymphoblastoma | <tumour> A malignant lymphoma arising from lymphoid follicular B-cells which may be small or large, growing in a nodular pattern. Synonym: follicular lymphoma, giant follicular lymphoblastoma. (05 Mar 2000) |
| giant follicular thyroiditis | A variant of Hashimoto's thyroiditis in which lymphocytic infiltrate in thyroid has formed into giant follicles. (05 Mar 2000) |
| giant gastric folds | Enlarged gastric submucosal ridges covered by hyperplastic mucosa, as seen in Zollinger-Ellison syndrome, Menetrier's disease, and hypertrophic hypersecretory gastropathy. (05 Mar 2000) |
| giant hairy nevus | <dermatology> These large pigmented (often hairy) congenital nevi are important because of their increased risk (10 to 15%) of conversion into malignant melanoma. A biopsy can confirm if cells have turned malignant. Any change in a pre-existing nevus should prompt a physician evaluation. (17 Dec 1997) |
| giant hives | A vascular reaction involving the deep dermis or subcutaneous or submucal tissues, representing localised oedema caused by dilatation and increased permeability of the capillaries and characterised by development of giant wheals. (18 Nov 1997) |