Polyposis of the colon and rectum.

P of the colon and rectum is considered to be a neoplastic disease manifested by the appearance of adenomatous mucosal polyps in various segments of the large intestine. Their significance lies in their tendency to ulcerate, bleed , induce diarrhea, cause abdominal cramps and transform into adenocarci noma. The lesion is an adenoma and it is the most common benign neoplasm in the large intestine where it may be found in all portions from childhood to old age and occurs also in the esophagus, stomach and small bowel. The tumors which do not arise from the mucus-secreting cell s of the colon and rectum are relatively few. The great majority of them are benign but whether benign or malignant, when the tumors project into the lumen where there is a mesentery and which do not splint the bowel wa ll , they may cause intussusception. Whenever the overlying mucosa is eroded by trauma or invasion, occult or patent bleeding will result. Such tumors are benign lymphoma, lipoma, endometrio is, leiomyoma, hemangioma, enterocy toma, carcinoid, lymphosarcoma and related condi t ions. All of the other benign tumors are curiosities of rare clinical importance. Secondary tumors resulting from metastases or direct invasion of the gut may simulate primary tumor especially in their pelvic course. These tumors are not discussed in this paper. Adenomas may be single, multiple, acquired or familial and appeal' pedunculated, sessile, smooth or vi llous, benign or malignant, of mucosal origin with the difference in morphology resulting from growth variation. Adenomas vary in size from a few millim tel's to several centimeters in