Small Bowel Malignant Tumors

Primary small bowel malignancies are rare compared with colorectal cancer. The most common types including carcinoid, adenocarcinoma, lymphoma, and GIST (gastrointestinal stromal tumor). The typical pattern of spread, imaging features, and response to the treatment are described in this chapter with highlighted differences between these tumors. The unique response pattern of GIST to tyrosine kinase inhibitors is better recorded using Choi criteria different from RECIST. Metastases from other malignancies commonly involve small bowel via direct peritoneal spread or distant hematogenous spread.