Premalignant States and Risk Factors
Several conditions and diseases are associated with an increased incidence of small bowel adenocarcinoma or lymphoma.
Regional Enteritis (Crohn’s Disease). Adenocarcinoma of the small bowel occurs more often in patients with regional enteritis than in age-matched controls and affects the ileum more often than the proximal bowel. Patients who have had segments of intestine bypassed surgically may be at higher risk.
Inherited Polyposis Syndromes. Several inherited intestinal polyposis syndromes are associated with an increased incidence of small intestinal adenocarcinoma. In familial adenomatous polyposis and Gardner’s syndrome, adenomas and adenocarcinomas of the duodenum occur with increased frequency, particularly in the periampullary region. Small intestinal (especially duodenal) adenocarcinoma has been reported in patients with Peutz-Jeghers syndrome, although the incidence is not high.
Celiac Sprue. An increased incidence of malignancy, especially lymphoma of the small intestine, has been reported in patients with celiac sprue. These lymphomas, derived from intestinal T cells, occur most frequently in the proximal small intestine. The association of celiac sprue with lymphoma has been questioned, because a diffuse intestinal lymphoma can also cause malabsorption, but evidence for this association is increasing. One study indicates that strict adherence to a gluten-free diet decreases the incidence of lymphoma.
Immune Deficiency States. An increased incidence of lymphoma of the small intestine has been suggested in hereditary syndromes of decreased humoral or cellular immunity and also in acquired immunodeficiency. The latter group includes patients with acquired immunodeficiency syndrome and those treated with intensive radiation, chemotherapy, and immunosuppressives.