Mucosal field change in colorectal cancer.

One hundred surgically excised colorectal carcinomas were examined histochemically using the high-iron diamine-alcian blue stain. Transitional mucosa surrounding the tumor was identified in 90 cases. The extent varied from 0 to 17 cm (mean 3.1 cm). In addition, the appearance of multiple patch lesions of increased sialomucin production was confirmed at sites far removed from the tumor in 35 cases. A predominant sialomucin pattern was seen in the proximal resection margin in 14 cases (17.9 percent), occurring as an isolated patch in 6 (43 percent). Sialomucin was also seen in the distal resection margin in 15 cases (15.9 percent), occurring as a direct extension of transitional mucosa surrounding the tumor in 12 (80 percent). These findings suggest that sialomucin production is a primary phenomenon that occurs as part of a field change in the human colon that develops cancer, and that these changes may occur in a resection margin and, by inference, remain at an anastomosis after resection.