Carcinoid tumors, vascular elastosis, and ischemic disease of the small intestine.

Ischemic enteritis or infarction occurred in four of 15 patients who had carcinoid tumors of the small intestine. All four, in addition, had elastic vascular sclerosis of the mesenteric vessels. Both arteries and veins were involved, and the change occurred in the region of tumor deposit. In none of the cases was the tumor occluding the lumen of the vessels, nor was there any evidence of thrombosis. Similar elastosis is seen in cancers of the colon, stomach, and breast, and occurs also with thermal injury and irradiation. The findings of the present study would suggest a direct rather than a humoral effect. It would appear that cancer cells exert an inductive effect on the fibroblast or smooth-muscle cell in vascular walls, with excess production of elastic tissue.