État précancéreux

A precancerous condition is a condition, tumor or lesion involving abnormal cells which are associated with an increased risk of developing into cancer. Clinically, precancerous conditions encompass a variety of abnormal tissues with an increased risk of developing into cancer. Some of the most common precancerous conditions include certain colon polyps, which can progress into colon cancer, monoclonal gammopathy of undetermined significance, which can progress into multiple myeloma or myelodysplastic syndrome. and cervical dysplasia, which can progress into cervical cancer. Bronchial premalignant lesions can progress to squamous cell carcinoma of the lung. Pathologically, precancerous tissue can range from benign neoplasias, which are tumors which don't invade neighboring normal tissues or spread to distant organs, to dysplasia, a collection of highly abnormal cells which, in some cases, has an increased risk of progressing to anaplasia and invasive cancer which is life-threatening. Sometimes, the term "precancer" is also used for carcinoma in situ, which is a noninvasive cancer that has not grown and spread to nearby tissue, unlike the invasive stage. As with other precancerous conditions, not all carcinoma in situ will become an invasive disease but is at risk of doing so. The term precancerous or premalignant condition may refer to certain conditions, such as monoclonal gammopathy of unknown significance, or to certain lesions, such as colorectal adenoma (colon polyps), which have the potential to progress into cancer (see: Malignant transformation). Premalignant lesions are morphologically atypical tissue which appear abnormal when viewed under the microscope, and which are more likely to progress to cancer than normal tissue. Precancerous conditions and lesions affect a variety of organ systems, including the skin, oral cavity, stomach, colon, lung, and hematological system.