This is a relatively newly recognized disease, and Cowden is a name of the reported family. The characteristics of this disease are 1)multiple papules on the face,2)small papules on the distal portion of the extremities,3)papillomatosis on the oral mucosa,4)digestive tract polyposis,5)hamartoma on the other organs, various mass lesions mainly composed of hyperplasia,6)hereditary, and so on. Also this disease is more likely to develop breast cancer, thyroid cancer, ovarian cancer, and gastrointestinal cancer. Especially among female patients, it is said that about 3/4 of them develop breast tumor, and about 2/3 of them develop goiter. Polyps are recognized in all the gastrointestinal tracts of the esophagus, stomach, small intestine, and large intestine, but diffuse development in the esophagus is pathognomonic finding. Histologically there are no pathognomonic findings, and this is called more like as glycogenic acanthosis in the esophagus.