Small-Intestine Tumors

Benign Tumors

Benign small-intestine tumors are rare, account for less than 5% of all GI tumors, and usually occur in the 5th, 6th, and 7th decades of life. About 80% of these tumors occur in the jejunum and ileum. Adenomatous polyps are the most common benign tumors, followed by leiomyoma, lipoma, and hemangioma. In the small intestine, as in the rest of the GI tract, adenomatous polyps are premalignant.

Most often, benign tumors are asymptomatic and are found during examination for unrelated symptoms or at autopsy. However, patients may present with recurrent abdominal pain, GI hemorrhage, abdominal mass, or intestinal obstruction. Diagnosis can be made by small-bowel x-ray. When the duodenum or terminal ileum is involved, small-bowel endoscopy may provide visualization and tissue for diagnosis.

Endoscopic or surgical resection is usually the treatment of choice, depending on the tumor's location.

Malignant Tumors

Cancers of the small intestine account for < 3% of all GI tract cancers and usually occur in the 6th and 7th decades. The most common is carcinoid tumor, followed by adenocarcinoma, lymphoma, and leiomyosarcoma. Lymphoma occurs predominantly in the ileum and is usually of B-cell origin; lymphoma of T-cell origin is associated with adult celiac disease. Leiomyosarcoma is as common as lymphoma.

Symptoms, Signs, and Diagnosis

Whereas most small-intestine cancers are asymptomatic, 60 to 75% of symptomatic small-intestine tumors are malignant. Patients with advanced disease present with abdominal pain resulting from intestinal obstruction, recurrent intussusception, mesenteric thrombosis, perforation, GI hemorrhage, or a palpable abdominal mass. The carcinoid syndrome, which is characterized by diarrhea and flushing, usually occurs when hepatic metastases develop. Lymphoma, especially Hodgkin's disease, may present as malabsorption syndrome with weight loss, diarrhea, malaise, weakness, and edema.

Preoperative diagnosis is generally made with a small-bowel x-ray series and CT. Endoscopy may provide visualization and tissue for diagnosis, and angiography may show vascular malignancies. In carcinoid tumors, urinary 5-hydroxyindoleacetic acid levels may be elevated.

Prognosis and Treatment

The 5-year survival rate for patients with adenocarcinoma is 30%; for those with lymphoma and leiomyosarcoma, it approaches 50%. Survival for patients with carcinoid tumors is commonly > 10 years.

Surgical resection is the usual treatment. Radiation therapy and chemotherapy are potentially effective only for lymphoma. In patients with carcinoid tumors, octreotide is often effective in treating severe flushing and diarrhea. Hepatic arterial chemoembolization with streptozocin or doxorubicin may be considered as palliative treatment in patients with hepatic metastases and preserved liver function.