Benign tumors of the small intestine

Most benign small intestinal tumors cause no symptoms and are incidentally found during radiographic or endoscopic examination, surgery, or autopsy.

Adenomas may be polypoid or sessile, similar to their colonic counterparts. The potential for malignant change, however, appears to be less for small intestinal than for colonic adenomas. Isolated adenomas may bleed intermittently, but because they are usually small and soft, they rarely cause obstruction. Most occur in the upper small bowel, and in some cases an experienced endoscopist can remove them via cautery snare.

Leiomyomas, benign smooth muscle tumors, sometimes occur throughout the small intestine. They may have a rich blood supply and ulcerate and bleed profusely. They may also obstruct the lumen. Usually they produce a smooth filling defect, which can be seen on barium radiograph, as they grow beneath the bowel mucosa. Sometimes leiomyomas ulcerate, producing an umbilicated so-called target lesion, seen on barium radiographic examination as a mass with a central ulceration. Leiomyomas should generally be removed surgically if they cause symptoms.

Neurofibromas may arise as isolated lesions or as part of von Recklinghausen's disease, in which multiple tumors are often present. Neurofibromas tend to grow outward into the serosa and may become large, causing the intestine to twist around them and become obstructed.

Hamartomas are benign growths that may contain all the cellular elements of the small bowel mucosa. Peutz-Jeghers syndrome is characterized by multiple hamartomatous polyps in the gastrointestinal tract. The polyps seem to increase in number as the patient grows older and may bleed, cause obstruction, or cause intussusception. If surgery is required for these complications, it is generally recommended that the length of resected bowel be kept to a minimum.

Duodenal glands (Brunner's glands) are submucosal and mucosal mucus-secreting glands that are most prominent in the duodenal bulb but may extend into the jejunum. Adenomas that develop in this tissue may form polypoid and even pedunculated tumors. A single adenoma may be associated with chronic gastric hyperacidity, but diffuse hyperplasia of Brunner's glands is more common. Duodenal gland adenomas may sometimes contain adipose tissue, in which case they are considered hamartomatous. Duodenal gland adenomas only rarely cause symptoms. Endoscopic observation and biopsy confirmation are usually all that is required for diagnosis; a pedunculated lesion can be removed endoscopically by cautery snare.

Author: Charles J. Lightdale

BIBLIOGRAPHY

_{Basson MD, Ahlman H, Wangberg B, Modlin IM: Biology and management of the midgut carcinoid, Am J Surg 165:288, 1993.}