Hyperplastic polyps are benign tumors of the small bowel, which in most cases grow slowly and remain asymptomatic. More rarely, the tumors might grow at a more rapid rate or grow larger than normal, causing symptoms such as pain and digestive problems. About 90 percent of all polyps found in the small bowel are hyperplastic. The remaining 10 percent are either adenomas, which are benign tumors that are of glandular origin, or are associated with a syndrome that leads to overgrowth of polyps.
The small bowel comprises approximately three-quarters of the length of the gastrointestinal tract, but very few malignant tumors arise here. Most tumors that develop in the small bowel are benign. Several types of tumors can develop in the various different sections of the small bowel, including adenomas, lipomas, hemangiomas, gastrointestinal stromal tumors and hyperplastic polyps.
Polyps can grow in any section of the small bowel, including the duodenum, jejunum and ileum. All tumor types, including hyperplastic polyps, are more likely to grow in the ileum than any other section. Generally, small bowel tumors are relatively isolated occurrences, with just one or a few forming. For some people, the development of polyps is part of hyperplastic polyposis syndrome, which leads to the growth of multiple polyps, often in all three sections of the small bowel.
Like most benign small bowel tumors, hyperplastic polyps tend to be asymptomatic. Rarely, a polyp might cause intestinal pain or gastrointestinal bleeding. Even more rarely, the growth of multiple tumors might lead to bowel obstruction or intussusception, in which one portion of bowel becomes displaced and slides into the next section.
Asymptomatic polyps often are discovered during a routine endoscopy or during an endoscopy carried out for purposes unrelated to the existence of the polyps. When polyps are discovered, they can be removed via relatively noninvasive methods such as endoscopy; open surgery is rarely required. In endoscopy, a thin tube equipped with surgical tools, a light source and a video camera is passed through the esophagus, past the stomach and into the small bowel. The surgeon uses the images generated by the camera to guide the tools and remove the polyps.
It is very rare for hyperplastic polyps to become malignant. Generally, only polyps associated with hyperplastic polyposis syndrome have the ability to become cancerous. A hyperplastic polyp has less than a one percent chance of becoming malignant. Even so, the presence of one or more polyps does increase the risk of colon cancer, so polyps often are removed after they are found, even if they are asymptomatic.