Usually, if more than 100 polyps develop in the colon, it is called polyposis of the large intestine. Consequently, if more than 100 hyperplastic polyps develop, it can safely be said that it is called hyperplastic polyposis. They are flat protuberances whose size is mostly less than 5mm,and the rising parts of lesions are, relatively clear. Regarding their shapes round to oval polyps are most common in polyps less than 5 mm, and the borders are irregular and erose, compared to adenoma. In polyps more than 6 mm, oval polyps whose borders are irregular are found further more, and irregularity of their borders becomes distinctive. Some lesions over 2cm in size exist in rare cases. Taking a look at the center of the lesion, their boundaries are indefinable, and their shapes are irregular with slight dent in many cases. In hyperplasic polyposis, it tends to be recognized not only they develop frequently in the whole colon but also relatively large lesions occur frequently. Also, in some cases of hyperplastic polyposis, they are recognized to be familial. In that case they are often associated with multiple cancers, epithelial dysplasia or adenomas, in the juveniles. For those reasons, familial hyperplastic polyposis is considered as a high risk group of cancers.