| giant cell granuloma | <dermatology, oncology> A non-neoplastic lesion characterised by a proliferation of granulation tissue containing numerous multinucleated giant cells. It occurs on the gingiva and alveolar mucosa (occasionally on other soft tissues) where it presents as a soft red-blue haemorrhagic nodular swelling. It also occurs within the mandible or maxilla as a unilocular or multilocular radiolucency. Peripheral giant cell granuloma refers to the gingiva (giant cell epulis), central refers to the jaw. Microscopically similar lesions occur in the tubular bones of the hands and feet, are considered neoplastic, and may have a malignant course. Identical bony lesions may be seen in hyperparathyroidism and cherubism. See: giant cell tumour of bone. Synonym: giant cell epulis. (05 Mar 2000) |
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| giant cell hepatitis | Hepatitis in the neonatal period presumed to be due to a variety of causes, chiefly viral; characterised by direct and indirect bilirubinaemia, hepatocellular degeneration, and appearance of multinucleated giant cells; may be difficult to distinguish from biliary atresia, but is more likely to end with recovery, although cirrhosis may develop. Synonym: giant cell hepatitis. (05 Mar 2000) |
| giant cell hyaline angiopathy | <pathology> An inflammatory infiltrate containing foreign body giant cells and eosinophilic material. Fragments of foreign material resembling vegetable matter may be included. Synonym: pulse granuloma. (05 Mar 2000) |
| giant cell monstrocellular sarcoma of Zulch | A histologic form of glioblastoma with large, often multinucleated, bizarre, tumour cells. Synonym: giant cell monstrocellular sarcoma of Zulch. (05 Mar 2000) |
| giant cell myeloma | 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 pneumonia | A rare complication of measles, with the postmortem finding of multinucleated giant cells lining alveoli. Synonym: Hecht's pneumonia, interstitial giant cell pneumonia. (05 Mar 2000) |
| giant cell sarcoma | <tumour> A malignant giant cell tumour of bone. (05 Mar 2000) |
| 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 cell thyroiditis | Thyroiditis with round cell (usually lymphocytes) infiltration, destruction of thyroid cells, epithelial giant cell proliferation, and evidence of regeneration; thought by some to be a reflection of a systemic infection and not an example of true chronic thyroiditis. Synonym: de Quervain's thyroiditis, giant cell thyroiditis. (05 Mar 2000) |
| 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) |
| 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 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) |