Hyperplastic Polyposis

What Is Hyperplastic Polyposis?

Individuals are diagnosed with hyperplastic polyposis when they have multiple hyperplastic polyps, usually greater than 20 polyps.  The number of polyps ranges anywhere from 6 to greater than 100, though most individuals with hyperplastic polyposis have between 40 and 100 polyps.  A diagnosis of Hyperplastic polyposis may also made in individuals who present with fewer than 20 hyperplastic polyps, but whose polyps are larger, often greater than 2 centimeters.  Individuals may also be diagnosed with multiple serrated adenomas or a mix of both serrated adenomas and hyperplastic polyps.  Hyperplastic polyposis is usually diagnosed in individuals in their 40’s to 60’s, though it has been reported in individuals as young as 11 years old.  Individuals with hyperplastic polyposis are at an increased risk for developing colorectal cancer, so routine screening is extremely important.  Although the genetic basis for FAP, HNPCC, Peutz-Jeghers, MYH-Associated Polyposis, and juvenile polyposis has been identified, hyperplastic polyposis has not yet been explained. Hyperplastic polyposis is suspected to have a familial basis and reports have shown that is inheritable in 5% of cases, though the exact mechanism of inheritance has not been identified.   

What are Hyperplastic and Sessile Serrated Polyps?

Hyperplastic polyps are not an uncommon polyp, and are often routinely found during colonoscopy screening.  The importance of the hyperplastic polyp as a precursor for colorectal cancer has not been well studied, though most evidence indicates that hyperplastic polyps are not generally associated with colorectal cancer.  Hyperplastic polyps are generally thought to be truly benign growths, possessing no potential for progression to colorectal cancer.  Contrast this with the adenoma, the colon polyp strongly associated with colorectal cancer, fewer than 10% of all adenomas become cancerous, however, more than 95% of colorectal cancers develop from adenomas. 

Hyperplastic polyps share similar features to a related polyp known as a sessile serrated adenoma.  Sessile serrated adenomas are related to hyperplastic polyps, but have dysplasia, this feature makes it more likely for a sessile serrated adenoma to progress to colorectal cancer than hyperplastic polyps.  While hyperplastic polyps are similar to sessile serrated adenomas, and other adenomas the research shows that the adenoma is clearly considered a precancerous colon polyp, whereas the hyperplastic polyp is considered to be benign, rarely progressing to colorectal cancer.   Click here to read more about the pathology of colon polyps

You can help with hyperplastic polyposis research!

The Johns Hopkins Hereditary Colorectal Cancer Registry is currently studying hyperplastic polyposis with the hope of better understanding this new syndrome.  If you have been diagnosed or are suspected of having hyperplastic polyposis or multiple hyperplastic polyps, please contact us for more information and to find out how you can help further our understanding of this syndrome. Please call us at 1-888-772-6566 or email us at hccregistry@jhmi.edu to find out more.