Association between colonic adenoma size and proliferative zone in the crypt

Abstract

Background

We previously reported unusual adenomas with proliferative zones confined to the lower two-thirds of the crypt. The proliferative zones of colorectal adenomas have three patterns: ‘lower,’ ‘superficial’ and ‘entire’. This study aimed to clarify the characteristics of each adenoma pattern.

Methods

We investigated 2925 consecutive patients who underwent colonoscopy at our institute. All polyps that were removed were histologically examined using hematoxylin and eosin staining. The location of the proliferative zone was assessed for adenomas. Data were compared using Dunn’s and Kruskal–Wallis tests.

Results

Colorectal adenomas with ‘lower’ proliferative zone often appeared similar to hyperplastic polyps (42.8%), and the frequency was significantly higher than that of adenomas with ‘superficial’ and ‘entire’ proliferative zones (p < 0.001). The mean sizes of adenomas were 2.4, 3.0 and 3.9 mm for ‘lower,’ ‘superficial’ and ‘entire’ proliferative zones, respectively. A significant gradual increase was observed. Regarding morphology, the proportion of type 0–I in adenomas with an ‘entire’ proliferative zone was significantly higher than that in adenomas with ‘superficial’ proliferative zone (p < 0.001).

Conclusion

While colorectal adenomas develop and increase in size, the proliferative zone appears to shift upward and become scattered.

Keywords:

• Colorectal adenoma
• proliferative zone
• polyp
• endoscopic diagnosis
• Japan narrow-band imaging expert team

Author contributions

TN analyzed the data and wrote the manuscript. HW performed pathological diagnosis. SY, and TM performed endoscopy. HE revised the manuscript. MF supervised the study. OT designed the study, and recruited patients.

Ethics approval

This retrospective study was approved by the Ethical Review Committee of the Yoyogi Mental Clinic (approval no. RKK227).

Informed consent statement

The request for comprehensive consent for use in medical research was published on our institute’s website (https://www.ichou.com/?p=7125), so that patients could opt out of the study.

STROBE statement

The authors have read the STROBE Statement checklist of items, and the manuscript was prepared and revised according to the STROBE Statement checklist of items.

Disclosure statement

No potential conflict of interest was reported by the author(s).