Dysplasia, or dysplastic changes, are atypical changes in the nuclei of cells (the inside of the cell that contains DNA), the cytoplasm (the portion of the cell surrounding the nuclei), or in the growth pattern of cells. These changes can be subtle or very pronounced. They are considered pre-cancerous changes (increases the risk of developing cancer.
Indefinite for dysplasia is an intermediate reading between negative and low-grade dysplasia. It simply means that the pathologist is not certain whether changes seen in the tissue are due to dysplasia. For example,inflammation of the lining of rectum and colon, perhaps from colitis, can make cells look atypical so that they resemble dysplastic cells although they are not dysplastic. The pathologist may see other signs of inflammation in the biopsy to help distinguish between inflammatory changes in the tissue and true dysplasia. Sometimes a pathologist may determine that dysplasia is difficult to grade due to inflammation and that is why your doctor wants to repeat the colonoscopy at a later date.
http://www.cancer.org/docroot/CRI/content/CRI_2_4_3x_Can_Colon_and_rectum_cancer_be_found_early.asp
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