Mucinous carcinomas of the colon and rectum and their relation to polyps.

A study of 44 mucinous carcinomas (MC) from a series of 324 colorectal cancers was made (221 surgical resections and 103 endoscopic biopsies). This study showed that MC were associated, in a significantly higher proportion when compared to non MC, with polypoid adenomas of different kinds (hyperplastic polyps not included), in other segments of the surgical specimen (P less than 0.001). MC originated from adenomas, particularly villous, but also mixed and tubular, in a significantly higher proportion than non-MC (P less than 0.001). Carcinomas arising from adenomas were mucinous in 11/14 cases. The type of adenomas from which MC arose were characterized by usually having areas with a particular arborizing mucus hyperplasia. At the time of resection, MC had metastases (Stages C and D) more frequently then non MC (P less than 0.02).