[Tumors of the small intestine].

Tumors of the small bowel are uncommon. Most of them are malignant neoplasmas with bad outcome. To ameliorate the doubtful prognosis tumors should be clarified carefully by means of histological, immunohistochemical and molecular methods. Patients suffering from familial adenomatous polyposis are at high risk to develop adenomas and adenocarcinomas of the duodenum. Therefore, the upper gastrointestinal tract should be monitored endoscopically in regular intervals. Surgically unresectable or metastatic malignant gastrointestinal stromal tumors should be included in an EORTC trial assessing the clinical activity of STI-571. This agent inhibits KIT-tyrosine kinase activity thus leading to a reduction of the tumor mass. Moreover, the WHO classification of lymphomas enables a more precise prognosis and individually tailored therapeutic strategies in primary lymphomas of the small bowel.