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Squamous-cell carcinoma or squamous-cell cancer (SCC or SqCC) is a cancer of a kind of epithelial cell, the squamous cell. These cells are the main part of the epidermis of the skin, and this cancer is one of the major forms of skin cancer. However, squamous cells also occur in the lining of the digestive tract, lungs, and other areas of the body, and SCC occurs as a form of cancer in diverse tissues, including the lips, mouth, esophagus, urinary bladder, prostate, lung, vagina, and cervix, among others. Despite sharing the name ''squamous-cell carcinoma'', the SCCs of different body sites can show tremendous differences in their presenting symptoms, natural history, prognosis, and response to treatment. SCC is a histologically distinct form of cancer. It arises from the uncontrolled multiplication of cells of epithelium, or cells showing particular cytological or tissue architectural characteristics of squamous-cell differentiation, such as the presence of keratin, tonofilament bundles, or desmosomes, structures involved in cell-to-cell adhesion. SCC is still sometimes referred to as "epidermoid carcinoma" and "squamous-cell epithelioma", though the use of these terms has decreased. SCC typically initially occurs in the sixth decade of life (the 50s), but is most common in the eighth decade (the 70s). It is twice as prevalent in men as in women. People with darker skin are less at risk to develop SCC. Populations with fair skin, light hair, and blue/green/grey eyes are at highest risk of developing the disease. Frequent exposure to direct, strong sunlight without adequate topical protection also increases risk.〔(【引用サイトリンク】title=Squamous Cell Carcinoma - Causes and Risk Factors )〕 ==Signs and symptoms== Symptoms are highly variable depending on the involved organs. SCC of the skin begins as a small nodule and as it enlarges the center becomes necrotic and sloughs and the nodule turns into an ulcer. *The lesion caused by SCC is often asymptomatic *Ulcer or reddish skin plaque that is slow growing *Intermittent bleeding from the tumor, especially on the lip *The clinical appearance is highly variable *Usually the tumor presents as an ulcerated lesion with hard, raised edges *The tumor may be in the form of a hard plaque or a papule, often with an opalescent quality, with tiny blood vessels *The tumor can lie below the level of the surrounding skin, and eventually ulcerates and invades the underlying tissue *The tumor commonly presents on sun-exposed areas (e.g. back of the hand, scalp, lip, and superior surface of pinna) *On the lip, the tumor forms a small ulcer, which fails to heal and bleeds intermittently *Evidence of chronic skin photodamage, such as multiple actinic keratoses (solar keratoses) *The tumor grows relatively slowly *Unlike basal-cell carcinoma (BCC), squamous-cell carcinoma (SCC) has a substantial risk of metastasis *Risk of metastasis is higher in SCC arising in scars, on the lower lips or mucosa, and occurring in immunosuppressed patients. About one-third of lingual and mucosal tumors metastasize before diagnosis (these are often related to tobacco and alcohol use). 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Squamous-cell carcinoma」の詳細全文を読む スポンサード リンク
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