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Ductal carcinoma in situ (DCIS), also known as intraductal carcinoma, is a pre-cancerous or non-invasive cancerous lesion of the breast. DCIS is classified as Stage 0.〔(Staging ), Breastcancer.org〕 It rarely produces symptoms or breast lumps, and it is usually detected through screening mammography. In this condition abnormal cells are found in the lining of one or more milk ducts in the breast. ''In situ'' means "in place" and refers to the fact that the abnormal cells have not moved out of the mammary duct and into any of the surrounding tissues in the breast (precancerous means that it has not yet become an invasive cancer). In some cases, DCIS may become invasive cancer and spread to other tissues, although it is not currently known how to predict which lesions will become invasive. DCIS encompasses a wide spectrum of diseases ranging from low-grade lesions that are not life-threatening to high-grade (i.e. potentially highly aggressive) lesions. DCIS has been classified according to architectural pattern (solid, cribriform, papillary, and micropapillary), tumor grade (high, intermediate, and low grade), and the presence or absence of comedo histology. DCIS can be detected on mammograms by examining tiny specks of calcium known as microcalcifications. Since suspicious groups of microcalcifications can appear even in the absence of DCIS, a biopsy may be necessary for diagnosis. About 20–30% of those who do not receive treatment develop breast cancer. It is the most common type of pre-cancer in women. There is some disagreement as to whether, for statistical purposes, it should be counted as a cancer: some include DCIS when calculating breast cancer statistics while others do not.〔(【引用サイトリンク】url=http://www.cancer.gov/cancertopics/pdq/treatment/breast/healthprofessional/page5/AllPages#Section_73 )〕 ==Terminology== Ductal carcinoma in situ (DCIS) is the name given to groups of "cancerous" epithelial cells that have remained in their normal place (''in situ'' in Latin) within the ducts and lobules of the mammary gland. Clinically, it is considered a premalignant (i.e. potentially malignant) condition. Each lesion contains cells that have already become biologically malignant ("cancerous") but have not yet crossed the basement membrane to invade the surrounding tissue.〔 When multiple lesions (known as "foci" of DCIS) are present in different quadrants of the breast, this is referred to as "multicentric" disease.〔 For statistical purposes, some count DCIS as a "cancer", whereas others do not.〔 When classified as a cancer, it is referred to as a non-invasive or pre-invasive form.〔 The National Cancer Institute describes it as a "noninvasive condition".〔 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「Ductal carcinoma in situ」の詳細全文を読む スポンサード リンク
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