Lymphomas arising from lymphoid tissues in the wall of the small bowel make up 14 percent of small bowel tumors. They may occur in any part of the small intestine and 20 percent of them develop in multiple sites. Of all the lymphomas that start somewhere other than in lymph nodes (extranodal lymphomas), 33 percent do so in the gastrointestinal tract, 10 percent in the small bowel. Most of these lesions are non-Hodgkin's lymphomas.
How It Spreads Small bowel cancers can spread directly through the bowel wall to adjacent tissues. Leiomyosarcomas grow in the muscle wall and extend to the surface (serosa). Sarcomas spread directly to the tissues supporting the bowel (mesentery), the retroperitoneum or the adjacent bowel. These cancers also spread through the lymphatic system and bloodstream to regional lymph nodes or to the liver, lungs or bone.
What Causes It There is an association with some inherited cancers and inflammatory bowel disease (Crohn's disease and celiac disease) and neurofibromatosis. Lymphomas are associated with immune deficiencies and celiac disease.
