History
The condition was originally known as hyperplastic polyposis syndrome. When the syndrome was first recognized, only hyperplastic polyps were included in its definition, and the syndrome was believed to not be associated with a higher risk of colorectal cancer. In 1996, a case series revealed an association of the syndrome with cancer and serrated adenomas. Subsequently, other types of serrated polyps were found to occur in this condition, so the name was adjusted to the present "serrated polyposis syndrome. "The World Health Organization released diagnostic criteria in 2010, which were updated in 2010 and again in 2019. The 2010 classification defined SPS as meeting any of the following criteria: 1) five or more serrated polyps proximal to the sigmoid colon with 2 larger than 10 mm in size, 2) any serrated polyps found proximal to the sigmoid colon in a person with a first-degree relative with serrated polyposis, or 3) more than 20 serrated colon polyps. The updated 2019 classification revised the first criterion to include lesions in the sigmoid colon, and excluded very small polyps (<5 mm). The updated 2019 classification also removed the criterion that included any serrated lesions proximal to the sigmoid colon in a person with a first degree relative with SPS. Epidemiology
Data regarding overall prevalence of SPS is lacking, but it is estimated to occur in roughly 1 in 100,000. SPS is equally common among men and women. Most individuals with SPS are diagnosed between 40 and 60 years of age, with an average age of 55 years.
Serrated polyposis syndrome (SPS), previously known as hyperplastic polyposis syndrome, is a disorder characterized by the appearance of serrated polyps in the colon. While serrated polyposis syndrome does not cause symptoms, the condition is associated with a higher risk of colorectal cancer (CRC). The lifelong risk of CRC is between 25 and 40%. SPS is the most common polyposis syndrome affecting the colon, but is under recognized due to a lack of systemic long term monitoring. Diagnosis requires colonoscopy, and is defined by the presence of either of two criteria: ≥5 serrated lesions/polyps proximal to the rectum (all ≥ 5 mm in size, with two lesions ≥10 mm), or >20 serrated lesions/polyps of any size distributed throughout the colon with 5 proximal to the rectum.A family history of SPS and smoking tobacco are associated with a higher risk of serrated polyposis syndrome, whereas the use of aspirin and nonsteroidal anti-inflammatory drugs (NSAIDs) are associated with a lower risk. While the only validated genetic cause of SPS is RNF43, additional important genetic abnormalities include BRAF mutations, abnormal CpG island methylator phenotype, and microsatellite instability. However, most individuals with the syndrome do not have an associated germline mutation. The types of polyps found in SPS include sessile serrated adenomas/polyps, traditional serrated adenomas, and hyperplastic polyps. SPS occurs in 2 phenotypes: proximal and distal. Proximal SPS has a greater risk of CRC than distal SPS. The vast majority of cases may be managed with colonoscopy with removal polyps (polypectomy).