Superficial-type adenomas and adenocarcinomas of the colon and rectum: a comparative morphological study

Gastroenterology. 1994 Jun;106(6):1436-43. doi: 10.1016/0016-5085(94)90395-6.

Abstract

Background/aims: It has been uncertain whether colorectal carcinomas preferentially arise on preexisting adenomas or de novo. However, from a morphological viewpoint, it seems unlikely that pedunculated or exophytic malignant polyps progress to the deeply ulcerated advanced carcinomas usually found clinically.

Methods: The morphological features of 26 nonpolypoid, superficial-type colorectal tumors (17 adenomas and 9 adenocarcinomas) were compared to clarify the developmental route of colorectal carcinomas.

Results: The adenomas and adenocarcinomas were very similar in size and gross appearance; however, examination of the surface appearances of unsectioned tumors by dissecting microscopy was helpful for distinguishing the two. Histologically, no adenomatous tissue was found in any case of superficial-type adenocarcinoma. Five of the nine adenocarcinomas, even including those of small size, invaded the submucosal layer, and two showed lymph node metastasis.

Conclusions: These findings suggest that superficial-type adenocarcinomas show rapid growth and aggressive behavior. We suggest that this type of carcinoma may not progress by the adenoma-to-carcinoma pathway but that it may arise from a very small superficial-type adenoma.

Publication types

  • Comparative Study

MeSH terms

  • Adenocarcinoma / pathology*
  • Adenoma / pathology*
  • Adult
  • Aged
  • Colonic Neoplasms / pathology*
  • Female
  • Humans
  • Lymphatic Metastasis
  • Male
  • Middle Aged
  • Neoplasm Invasiveness
  • Rectal Neoplasms / pathology*