"Adenoma - carcinoma sequence" is seen in

(Carcinoma colon) (1177-LB) (1179-B &L 25th)Adenocarcinoma of the colon: microscopically the neoplasm is a columnar cell carcinoma originating in the colonic epithelium. Macroscopically, the tumour may take one of four forms. Type 4 is the least malignant form* It is likely that all carcinomas start as benign adenoma the so called "adenoma-carcinoma sequence"* The annular variety tends to give rise to obstructive symptoms whereas the others more commonly willpresent with bleeding.* Tumours are more common in the left colon and rectum.