Nuclear changes in colo-rectal epithelium with special reference to nuclear inclusions in carcinoma, dysplasia, adenoma and Peutz-Jeghers polyps.

The incidence and types of unusual nuclear structures (UNS) were examined based on the observation of randomly photographed 1,919 nuclei in total from the normal epithelium, dysplasia, Peutz-Jeghers type polyp, adenoma and carcinoma of the large bowel. These nuclear structures were classified as filamentous, granular and vesicular inclusions, and invaginated structures were also taken into consideration. Although all types of UNS were found in the normal epithelium, carcinoma cells had the most numerous UNS, especially of the invaginated type. The possible process of nuclear inclusion (NI) formation was discussed in connection with malignant transformation of colo-rectal epithelial cells.