A hyperplastic polyp is a common benign (non-cancerous) growth that develops on the inner lining of the large intestine, which includes the colon and the rectum. Hyperplastic polyps are not precancerous. They do not contain the abnormal cells that lead to cancer, and for most people, finding one does not change the colorectal cancer screening schedule at all.
The word hyperplastic means overgrown. The cells in these polyps have multiplied more than usual, producing a small bump on the colon lining, but the cells themselves still look essentially normal under the microscope. That is what separates a hyperplastic polyp from a precancerous polyp such as a tubular adenoma or a sessile serrated lesion, in which the cells are genuinely abnormal. This article explains the findings you may see in a pathology report after a hyperplastic polyp has been removed and when, if ever, this diagnosis changes your follow-up.
No. A hyperplastic polyp is benign, which means it is neither cancer nor precancerous. It will not turn into cancer, and it does not spread. In this respect, it differs from every other polyp described elsewhere in this section of the site, all of which carry some risk of progressing over time.
Hyperplastic polyps belong to a family of growths called serrated polyps, named for the saw-tooth pattern their glands show under the microscope. The other members of that family, the sessile serrated lesion and the traditional serrated adenoma, are precancerous. The hyperplastic polyp is the exception, and most of the attention it gets in a pathology report is making sure it hasn’t been confused with one of the others.
Hyperplastic polyps form when cells in the colon lining grow and divide more than usual, producing a small overgrowth. The exact cause is not fully known. Factors that increase the likelihood of developing one include:
Most hyperplastic polyps cause no symptoms. They are usually small, typically under 5 mm, and are often found incidentally during a colonoscopy performed for routine screening or for an unrelated reason. A large hyperplastic polyp occasionally causes rectal bleeding or a change in bowel habits, but this is uncommon.
Hyperplastic polyps occur most often in the rectum and sigmoid colon, the lower left part of the large intestine. They are less common on the right side of the colon, meaning the ascending colon and cecum.
Location is recorded on your report for one specific reason. A hyperplastic polyp on the right side can be difficult to tell apart from a sessile serrated lesion, which is precancerous and also favors the right colon. The two look similar near the surface and differ mainly at the base of the glands, so a small or fragmented sample can leave the distinction unresolved. When a right-sided polyp is small and the diagnosis is confident, guidelines treat it the same as a left-sided one. When the polyp is 10 mm or larger and sits above the sigmoid colon, many gastroenterologists manage it as though it were a sessile serrated lesion, because the chance of misclassification is high enough to matter.
The diagnosis of a hyperplastic polyp is made only after the polyp has been removed and examined under a microscope by a pathologist. During a colonoscopy, a polypectomy removes the polyp using a small wire loop passed through the scope, or biopsy forceps for very small polyps.
Under the microscope, a hyperplastic polyp shows tightly packed glands with a saw-tooth outline near the surface of the lining. The cells are mature and well organized, and they produce mucin, the substance that normally lubricates the colon. The base of the glands looks entirely normal, with straight, regularly spaced crypts. This normal base is the finding that separates a hyperplastic polyp from a sessile serrated lesion, where the crypts widen and turn sideways at the bottom. The pathologist also confirms there is no dysplasia, the abnormal cell change that marks a polyp as precancerous.
Because a hyperplastic polyp is benign, no imaging scans or additional tests are needed after the diagnosis.
Your report may name one of two subtypes of hyperplastic polyp. Both are distinguished only by how the cells look under the microscope:
These subtypes behave the same way and carry the same significance. The distinction is recorded for classification purposes and does not affect your treatment or your follow-up. Many reports do not mention a subtype at all.
Two findings recorded after a hyperplastic polyp is removed can affect your follow-up: its size and the number of polyps found.
Size is usually reported in millimeters. Most hyperplastic polyps are under 5 mm and nothing further follows from them. The key threshold is 10 mm. A hyperplastic polyp of 10 mm or larger is uncommon, and it raises the possibility that the polyp is actually a sessile serrated lesion that could not be classified with certainty, which is why it leads to earlier follow-up.
Number matters at much higher counts than for other polyps. Finding a handful of small hyperplastic polyps in the rectum or sigmoid colon is normal and doesn’t change anything. Finding more than twenty raises the possibility of serrated polyposis syndrome, a condition defined by either at least five serrated polyps above the rectum with two or more of them 10 mm or larger, or more than twenty serrated polyps of any size spread throughout the colon. It is uncommon, it carries an increased risk of colorectal cancer, and it leads to much closer surveillance along with screening for family members.
The margin is the cut edge of the tissue that was removed. For a hyperplastic polyp, most reports do not mention the margin at all. Pathologists assess margins when tissue left behind could go on to become cancer, and that does not apply here. These polyps are also usually small and are often removed with forceps or a snare in a way that leaves no clean edge to evaluate.
If your report does comment on the margin, a positive or unassessable result does not carry the weight it would for a precancerous polyp, because benign tissue left at the site is not on a path toward cancer. It rarely prompts a repeat procedure. Your doctor will confirm whether your case needs follow-up at the removal site.
Three types of polyps make up the serrated family, and telling them apart is why a hyperplastic polyp gets careful attention under the microscope.
Pathologists do not always agree on where the line falls between a hyperplastic polyp and a sessile serrated lesion, particularly when the sample is small or poorly oriented. This is a recognized limitation of the microscope rather than an error, which is why follow-up recommendations for large or right-sided serrated polyps err on the side of caution.
In most cases, no additional treatment is needed after a hyperplastic polyp is removed, and no change is made to your screening schedule. Current guidelines from the US Multi-Society Task Force on Colorectal Cancer group findings roughly as follows:
If other polyps were found at the same colonoscopy, those findings set your schedule instead, since adenomas and sessile serrated lesions carry more weight than a hyperplastic polyp. The quality of the examination also matters. If the bowel preparation was poor or the colonoscopy could not be completed, your doctor may recommend repeating it sooner. Your pathology report is one of several things your doctor weighs when setting the plan, and what happens after your pathology report describes the wider process.