| carcinoma, infiltrating duct | An invasive (infiltrating) carcinoma of the breast. This carcinoma in which no special histological feature is recognised is designated nos or not otherwise specified and is by far the most common ductal tumour, accounting for almost 70% of breast cancers. It is characterised by stony hardness upon palpation. It commonly metastasizes to the axillary lymph nodes and its prognosis is the poorest of the various ductal types. (12 Dec 1998) |
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| carcinoma in situ | Cancer that involves only the cells in which it began and has not spread to other tissues. Lobular carcinoma in situ is found in the lobules of the breast. Ductal carcinoma in situ (also called intraductal carcinoma) arises in the ducts. (16 Dec 1997) |
| carcinoma, intraductal, noninfiltrating | A noninvasive (noninfiltrating) carcinoma of the breast characterised by a proliferation of malignant epithelial cells confined to the mammary ducts or lobules, without light-microscopy evidence of invasion through the basement membrane into the surrounding stroma. Its true incidence is uncertain but all noninvasive breast carcinomas comprise almost 5% of all neoplastic lesions of the female breast, with this carcinoma accounting for about 50% of these, or 2.5%-2.8% of all tumours. (12 Dec 1998) |
| carcinoma, islet cell | A carcinoma of the islets of langerhans. (12 Dec 1998) |
| carcinoma, large cell | A tumour of undifferentiated (anaplastic) cells of large size. It is usually bronchogenic. (12 Dec 1998) |
| carcinoma, lewis lung | A carcinoma discovered by dr. Margaret r. Lewis of the wistar institute in 1951. This tumour originated spontaneously as a carcinoma of the lung of a c57bl mouse. The tumour does not appear to be grossly haemorrhagic and the majority of the tumour tissue is a semifirm homogeneous mass. It is also called 3ll and llc and is used as a transplantable malignancy. (12 Dec 1998) |
| carcinoma, lobular | A infiltrating (invasive) breast cancer, relatively uncommon, accounting for only 5%-10% of breast tumours in most series. It is often an area of ill-defined thickening in the breast, in contrast to the dominant lump characteristic of ductal carcinoma. It is typically composed of small cells in a linear arrangement with a tendency to grow around ducts and lobules. There is likelihood of axillary nodal involvement with metastasis to meningeal and serosal surfaces. (12 Dec 1998) |
| carcinoma, medullary | A carcinoma composed mainly of epithelial elements with little or no stroma. Medullary carcinomas of the breast constitute 5%-7% of all mammary carcinomas; medullary carcinomas of the thyroid comprise 3%-10% of all thyroid malignancies. (12 Dec 1998) |
| carcinoma, merkel cell | A carcinoma arising from merkel cells located in the basal layer of the epidermis and occurring most commonly as a primary neuroendocrine carcinoma of the skin. Merkel cells are tactile cells of neuroectodermal origin and histologically show neurosecretory granules. The skin of the head and neck are a common site of merkel cell carcinoma, occurring generally in elderly patients. (12 Dec 1998) |
| carcinoma, mucoepidermoid | A tumour of both low- and high-grade malignancy. The low-grade grow slowly, appear in any age group, and are readily cured by excision. The high-grade behave aggressively, widely infiltrate the salivary gland and produce lymph node and distant metastases. Mucoepidermoid carcinomas account for about 21% of the malignant tumours of the parotid gland and 10% of the sublingual gland. They are the most common malignant tumour of the parotid. (12 Dec 1998) |
| carcinoma myxomatodes | An obsolete term for a form of colloid cancer in which there is myxomatous metaplasia of the cellular fibrous stroma. (05 Mar 2000) |
| carcinoma, neuroendocrine | A group of carcinomas which share a characteristic morphology, often being composed of clusters and trabecular sheets of round "blue cells", granular chromatin, and an attenuated rim of poorly demarcated cytoplasm. Neuroendocrine tumours include carcinoids, small ("oat") cell carcinomas, medullary carcinoma of the thyroid, merkel cell tumour, cutaneous neuroendocrine carcinoma, pancreatic islet cell tumours, and pheochromocytoma. Neurosecretory granules are found within the tumour cells. (12 Dec 1998) |
| carcinoma, non-small-cell lung | A heterogeneous aggregate of at least three distinct histological types of lung cancer, including squamous cell carcinoma, adenocarcinoma, and large cell carcinoma. They are dealt with collectively because of the shared properties of poor response to conventional chemotherapy and the potential for cure with surgical resection in a fraction of patients. (12 Dec 1998) |
| carcinoma, renal cell | Carcinoma of the renal parenchyma usually occurring in middle age or later and composed of tubular cells in varying arrangements. It was first described in 1826. Possible causal factors are environmental, hormonal, cellular, and genetic. Smoking is a definite risk factor and obesity is associated with increased risk. Renal cell carcinoma accounts for approximately 3% of adult cancer; the male-female ratio is 2:1. It is more common among urban residents than rural. (12 Dec 1998) |
| carcinoma, signet ring cell | A highly malignant, mucus-secreting tumour in which the mucus-secreting cells are anaplastic and appear rounded, with the nucleus displaced to one side by a globule of mucus in the cytoplasm. (12 Dec 1998) |