The effects of therapeutic radiation on colonic mucosa.

Low to moderate doses of therapeutic irradiation are capable of producing bizarre cytologic changes in the mucosal cells of colorectal crypts. This may be associated with eosinophilia of the lamina propria and with eosinophilic crypt abscesses. The bizarre cells generally line intact crypts and do not exhibit invasive behavior. The change subsides within 1-2 months at the dose levels studied (approximately 2000 rads).