Small intestine cancer begins in the small bowel, the longest section of the GI system. Its function is to absorb nutrients from the food we eat. There are five types of small intestine cancers: adenocarcinoma, the most common, which begins in the glandular cells that line the intestines; leiomyosarcoma, which develops in the smooth muscle cells; carcinoid tumors, a type of neuroendocrine cancer; GI Stromal Tumors; and lymphoma, which begin in the immune system cells.
Adenocarcinoma cancers of the small intestines are thought to develop from a polyp, a benign growth on the GI wall that over time can become malignant. Most of these cancers develop in the duodenum, the first section of the small bowel that connects with the stomach.
Blood in the stool
A lump in the abdomen