| malignant lymphoma | <tumour> A general term for ordinarily malignant neoplasms of lymphoid and reticuloendothelial tissues which present as apparently circumscribed solid tumours composed of cells that appear primitive or resemble lymphocytes, plasma cells, or histiocytes. Lymphomas appear most frequently in lymph nodes, spleen, or other normal sites of lymphoreticular cells; when disseminated, Lymphoma's, especially of the lymphocytic type, may invade the peripheral blood and manifest as leukaemia. Lymphomas are classified by cell type, degrees of differentiation, and nodular or diffuse pattern; Hodgkin's disease and Burkitt's lymphoma are special forms. (05 Mar 2000) |
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| malignant malnutrition | A nutritional deficiency illness in children who are not getting enough protein, this results in anaemia, poor growth, weakness, and oedema (which isparticularly characterised by a pronounced pot belly). Infamine-stricken regions, children typically develop kwashiorkor rightafter they are weaned. (09 Oct 1997) |
| malignant melanoma | <oncology, tumour> A malignant tumour which arises from the pigment producing cells (melanosomes) of the deeper layers of the skin (or the eye). Melanoma is the leading cause of death attributable to skin lesions. Described as an irregular dark skin lesion that may have areas of varying colour. Often greater than 6 mm in diameter. (27 Sep 1997) |
| malignant melanoma: gallium imaging | <radiology> Greater than50% sensitivity for primary and metastatic sites: 73% sensitivity if lesion is greater than 2 cm, 17% sensitivity if less than 2 cm, see: gallium: indications malignant melanoma (12 Dec 1998) |
| malignant melanoma in situ | A melanoma limited to the epidermis and composed of nests of atypical melanocytes and scattered single cells extending into the upper epidermis; local excision is curative although the lesion, if untreated, may soon invade the dermis. Malignant lentigo may be considered a slowly progressive type of malignant melanoma in situ. (05 Mar 2000) |
| malignant melanoma: staging | <radiology> Clark staging: level I: all tumour cells above basement membrane (in situ), level II: tumour extends to papillary dermis, level III: tumour extends to interface between papillary and reticular dermis, level IV: tumour extends between bundles of collagen of reticular dermis, level V: tumour invasion of sucutaneous tissue (87% metastases) Breslow staging: thin: less than 0.75 mm depth of invasion, intermediate: 0.76 - 3.99 mm depth of invasion, thick: greater than 4 mm depth of invasion see: malignant melanoma (12 Dec 1998) |
| malignant meningioma | <tumour> Meningioma that either invades brain parenchyma or metastasizes. (05 Mar 2000) |
| malignant mesothelioma | <oncology, tumour> A mesothelioma is a tumour of the lining of the lung and chest cavity, known as the pleura. Benign mesotheliomas do occur but are much more rare than the malignant type. Malignant mesothelioma affects men more commonly and about 80% of cases have a history for prior exposure to asbestos. Symptoms include chest pain, shortness of breath, cough and weight loss. (27 Sep 1997) |
| malignant midline reticulosis | An obsolete term for polymorphic reticulosis (05 Mar 2000) |
| malignant mixed mullerian tumour | A sarcoma of the body of the uterus arising in older women, composed of more than one mesenchymal tissue, especially including striated muscle cells. Synonym: malignant mixed mullerian tumour. (05 Mar 2000) |
| malignant mole syndrome | <syndrome> Irregularly shaped, variously coloured, distinctively melanocytic, 5 to 10 mm nevi occurring in large numbers (to over 100) primarily on the trunk and extremities, with a high risk of malignancy reported in several members and three generations of a family. (05 Mar 2000) |
| malignant myopia | pathologic myopia |
| malignant nephrosclerosis | The renal changes in malignant hypertension; subcapsular petechiae, necrosis in the walls of scattered afferent glomerular arterioles, and red blood cells and casts in the urine, with uraemia as a common termination. (05 Mar 2000) |
| malignant oedema | An acute toxaemia of cattle, horses, sheep, goats, and pigs caused by the bacterium Clostridium septicum and characterised by edematous swellings around the entry wound, anorexia, high fever, and death. (05 Mar 2000) |
| malignant pustule | The skin of B. Anthracis infection characteristic lesion that begins as a papule and soon becomes a vesicle and breaks, discharging a bloody serum; the seat of this vesicle, in about 36 hours, becomes a bluish black necrotic mass; constitutional symptoms of septicaemia are severe: high fever, vomiting, profuse sweating, and extreme prostration; the infection is often fatal. Synonym: malignant pustule. (05 Mar 2000) |