Mesenteric neuroendocrine deposits are "cicatrising" - they induce a fibrotic reaction in the mesentery and cause indrawing and tethering of adjacent small bowel loops. They can also compromise the vascular supply and drainage, causing ischemia. Once the tumors metastasize to the liver, patients are prone to carcinoid syndrome as the liver no longer acts as a filter for the secreted hormones.