Cancer in readily observable regions, as the mouth, arises from a preexisting benign lesion, a papilloma, a small ulcer or a point of constant irritation. It seems probable that this holds good in the more inaccessible regions of the body, where early observation is difficult or impossible. In a patient of mine, Mrs. C. C. S., with advanced cancer of the transverse colon, there were several small adenomas near the cancer (figs. 1 and 2). The histologic structure of one of these adenomas showed that, while the growth was benign, there was a tendency to hyperplasia of the epithelial cells (fig. 3). It is a logical conclusion that the cancerous lesion of the colon originated in an adenoma like this.
SYMPTOMS AND SIGNS
Often the first symptom of carcinoma of the colon is obstruction. This is usual when there is a scirrhous cancerous stricture. A disturbance of the bowel movements