Small-Bowel Tumors

Benign tumors include leiomyomas, lipomas, neurofibromas, and fibromas. All may cause abdominal distention, pain, bleeding, diarrhea, and, if obstruction develops, vomiting. Polyps are not as common as in the colon.

Adenocarcinoma, a malignant tumor, is uncommon. Usually it arises in the duodenum or proximal jejunum and causes minimal symptoms. In patients with Crohn disease involving the small-bowel, the tumors tend to occur distally and in bypassed or inflamed loops of bowel.

Primary malignant lymphoma Overview of Lymphoma Lymphomas are a heterogeneous group of tumors arising in the reticuloendothelial and lymphatic systems. The major types are Hodgkin lymphoma Non-Hodgkin lymphoma See table Comparison of Hodgkin... read more arising in the ileum may cause a long, rigid segment. Small-bowel lymphomas can arise in long-standing, untreated celiac disease Celiac Disease Celiac disease is an immunologically mediated disease in genetically susceptible people caused by intolerance to gluten, resulting in mucosal inflammation and villous atrophy, which causes malabsorption... read more .

Gastrointestinal neuroendocrine tumors (previously known as carcinoid tumors Overview of Carcinoid Tumors Carcinoid tumors develop from neuroendocrine cells in the gastrointestinal tract (90%), pancreas, pulmonary bronchi, and rarely the genitourinary tract. More than 95% of all gastrointestinal... read more ) occur most often in the small bowel, particularly the ileum, and in the appendix; in these locations, larger lesions can become malignant. Multiple tumors occur in 50% of cases. Of those > 2 cm in diameter, 80% have metastasized locally or to the liver by the time of operation. About 30% of small-bowel neuroendocrine tumors cause obstruction, pain, bleeding, or carcinoid syndrome Carcinoid Syndrome Carcinoid syndrome develops in some people with carcinoid tumors and is characterized by cutaneous flushing, abdominal cramps, and diarrhea. Right-sided valvular heart disease may develop after... read more . Treatment of these tumors depends on the site of origin. Small-bowel neuroendocrine tumors are surgically resected; repeat operations may be required, and, in many cases, more than one segment of small intestine is involved. Gastric neuroendocrine tumors, unlike those of the small intestine, can be managed with endoscopic resection if they are small and associated with chronic atrophic gastritis (eg, type 1 disease). Similarly, small rectal neuroendocrine tumors sometimes can be removed endoscopically. For metastatic neuroendocrine tumors, long-acting somatostatin analog therapy with dose escalation, peptide receptor radioligand therapy (PRRT) using a radiolabeled somatostatin analog, or everolimus can be used to effectively control the disease.

Kaposi sarcoma Kaposi Sarcoma Kaposi sarcoma is a multicentric vascular tumor caused by herpesvirus type 8. It can occur in classic, AIDS-associated, endemic (in Africa), and iatrogenic (eg, after organ transplantation)... read more , occurs in an aggressive form in patients who are immunocompromised (eg, transplant recipients, patients with uncontrolled AIDS). Lesions may occur anywhere in the GI tract but usually in the stomach, small bowel, or distal colon. GI lesions usually are asymptomatic, but bleeding, diarrhea, protein-losing enteropathy, and intussusception may occur. Treatment of Kaposi sarcoma Treatment Kaposi sarcoma is a multicentric vascular tumor caused by herpesvirus type 8. It can occur in classic, AIDS-associated, endemic (in Africa), and iatrogenic (eg, after organ transplantation)... read more depends on the cell type and location and extent of the lesions.