Key Concepts

• The majority of gastrointestinal stromal tumors (GISTs) stain positive for CD117 and have an alteration in c-kit proto-oncogene.
• Surgical excision with a 1–2 cm margin is the preferred treatment for GISTs located in the rectum.
• Treatment of midgut neuroendocrine tumors (NETs) is segmental resection with lymphadenectomy.
• Somatostatin analogs control the symptoms of carcinoid syndrome and help limit the progression of disease.
• Rectal NETs less than 1 cm in diameter may be treated by endoscopic or local excision, while tumors greater than 2 cm should be considered for radical resection.
• Patients with symptomatic colonic lymphomas are best treated with surgical resection prior to chemotherapy.