This is a disease of digestive tract polyposis associated with ectodermal lesions such as hair loss, and atrophy and shedding of nail plates, generalized pigmentation and so on. This is not inheritable, and they develop with diarrhea, taste abnormality or hyposalivation mostly among middle-aged / senior persons. Generally considered, though there is no malignant findings pathologically, this has been clinically regarded as a disease of a poor prognosis because protein-losing gastropathy was presented, and fatal cases were recognized in about 1/4 of all the cases in the past. Usually polyps develop diffusely, in all the gastrointestinal tracts except the esophagus. Mucous membranes swell in a hexagonal way, and giant folds and various sizes of polyps on them are seen. Changes in the hirsutulous pattern of the borders are recognized, which are often seen in the stomach. There is no variant form histogenetically, and cystic dilation of the gland tracts caused by excessive secretion of mucus and interstitial edema are marked. Consequently histologies of polyps tend to be similar to juveniles polyps, and hyperplasias of the gland tract is also often seen with them. However, the cases associated with adenomas in a part of lesions or the cases of complications of colorectal cancers are reported in about 10% of the cases. Meanwhile, digestive tract polyposis and ectodermal lesions like nails or hairs, and pigmentation, can subside after treatment, and are also reversible.