melanoma(redirected from in situ melanoma)
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melanoma:see skin cancerskin cancer,
malignant tumor of the skin. The most common types of skin cancer are basal cell carcinoma, squamous cell carcinoma, and melanoma. Rarer forms include mycosis fungoides (a type of lymphoma) and Kaposi's sarcoma.
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melanoblastoma; a malignant tumor that consists of melanin-producing cells.
Factors conducive to the development of melanomas include injury and hormonal stimulation, especially during puberty. Melanomas generally occur on the skin; less often, they appear on the retina, pia mater, nasopharynx, larynx, esophagus, and mucosa of the intestine and other organs. Melanomas usually develop at the site of pigmented or depigmented birthmarks, but they may also appear elsewhere. The process starts with a barely perceptible, painless tumor on the skin, sometimes resembling a wart, which gradually becomes dark brown or black. Occasionally, it ulcerates and bleeds. In case of injury, the tumor may enlarge quickly and become tuberous, dense at the base, and stiffer. The regional lymph nodes enlarge. The initial signs that a melanoma is developing at the site of a birthmark are the birthmark’s enlargement, an intensification or reduction in its pigmentation, and the appearance of a red rim around it. Treatment involves prompt surgical intervention, based on early diagnosis, and the use of radiotherapy and drugs to retard the growth and reproduction of the cells.
I. IA. SHAKHTMEISTER