Tumors of the small intestine

Small intestinal tumors account for 1-5% of gastrointestinal tumors.

Benign tumors include leiomyomas, lipomas, neurofibromas, and fibromas. All can cause bloating, pain, bleeding, diarrhea, and, if obstructed, vomiting. Polyps are not as common as in the colon.

Adenocarcinoma is not a common malignancy. It usually develops in the duodenum or proximal jejunum and causes minimal symptoms. In patients with Crohn's disease, tumors tend to develop distally and in disconnected and inflamed loops of bowel; adenocarcinoma occurs more frequently in small-bowel Crohn's disease than in colonic Crohn's disease.

Primary malignant lymphoma that develops in the ileum and manifests as an extended rigid segment of the intestine. Small intestinal lymphomas often occur in the long-term course of untreated celiac disease.

Carcinoid tumors develop most frequently in the small intestine, especially the ileum and appendix, and are often malignant in this location. Multiple tumors are observed in 50% of cases. In 80% of cases of tumors larger than 2 cm in diameter, regional metastasis is observed, and by the time of surgery, it has also spread to the liver. In approximately 30% of cases, small intestinal carcinoids cause obstruction, pain, bleeding, or carcinoid syndrome. Treatment consists of surgical resection; repeat operations may be necessary.

Kaposi's sarcoma, originally described as a disease of elderly Jewish and Italian men, develops in an aggressive form in Africans, transplant recipients, and AIDS patients, in whom 40% to 60% have preexisting GI disease. The disease may occur anywhere in the GI tract, but most commonly in the stomach, small bowel, or distal colon. GI disease is usually asymptomatic, but bleeding, diarrhea, protein-losing enteropathy, and intussusception may develop. A second primary intestinal malignancy develops in < 20% of patients; most commonly, lymphocytic leukemia, non-Hodgkin's lymphoma, Hodgkin's disease, or GI adenocarcinoma. Treatment depends on the cell type, location, and extent of involvement.

Diagnosis and treatment of small intestine tumors

Enteroclysm is probably the primary investigation for large lesions of the small bowel. Balloon endoscopy of the small bowel with enteroscopy may be used to visualize and biopsy the tumor. Videoendoscopy with a capsule helps identify small bowel lesions, especially areas of bleeding; a swallowed capsule transmits 2 images per second to an external recording device. Use of a capsule for examination of the stomach and colon is impractical, since the capsule inverts in these large organs.

Treatment consists of surgical resection. Electrocoagulation, thermal obliteration or laser phototherapy during enteroscopy or surgery may be alternatives to resection.

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