Evaluation of tumor development from the viewpoint of the three-dimensional configuration of isolated crypts in colorectal adenomas with a type IIIl pit pattern

Abstract

Background

The relationship between the three-dimensional configurations of superficial and protruded-type colon tumors with a type IIIl pit pattern was examined to evaluate their morphological development.

Methods

Forty-five isolated crypts of superficial-type adenomas and 65 isolated crypts of protruded-type adenomas were evaluated, all derived from segments of 12 colorectal lesions removed by surgery or endoscopic resection. For isolation of the crypts, an HCl-digestion method was used. Morphological features of the isolated crypts were observed by scanning electron microscopy (SEM). We investigated the configuration, length, and width of the isolated crypts in a comparison of the superficial and protruded-type tumors. The configuration and surface structure of the crypts were classified into three types (scores 1 to 3) by the shape and degree of branching and protuberances on their surface.

Results

The average lengths of the isolated crypts of the superficial and protruded types were 310.9 ± 122.9 µm (n = 45) and 434.4 ± 163.3 µm (n = 65), respectively (P < 0.001), and the average widths of the superficial and protruded types were 140.4 ± 68.2 µm and 171.5 ± 73.3 µm, respectively (P = 0.02). The average scores for the degree of branching and protruberances in the superficial and protruded types were 1.178 ± 0.442 and 1.569 ± 0.529, respectively (P < 0.0001). In terms of configuration, in the isolated crypts, the superficial-type tumors exhibited a two-layer structure and the protruded type had the shape of a spindle with protuberances.

Conclusions

In colorectal tumors with a type IIIl pit pattern, the isolated crypts of protruded-type tumors displayed more roughness on their surface structure and were longer than those of superficial-type tumors. This suggested that the three-dimensional configuration of the isolated crypt constitutes an important factor in the formation of the gross configuration of colorectal tumors. Colorectal superficial and protruded-type tumors may develop with different growth patterns.