Serrated polyposis syndrome; epidemiology and management

Serrated colorectal polyps, long considered innocent, are currently recognized as the precursors to one-third of all colorectal cancers (CRC). Serrated polyposis syndrome (SPS), characterized by accumulation of multiple and/or large serrated polyps, symbolizes the highest expression of serrated pathway of carcinogenesis, leading to a high risk of CRC when it is not detected or treated on time. Although previously considered uncommon, SPS is now acknowledged as the most prevalent colorectal polyposis. This syndrome has attracted increasing interest over the past decade and has become a hot topic in the field of gastrointestinal oncology. Besides a small proportion of cases caused by germline mutations in RNF43, no clear genetic cause has been identified. Both epigenetic and environmental factors, especially smoking, have been related to this syndrome, but the etiology of SPS remains uncertain and diagnosis is based on endoscopic criteria. Recent studies on SPS have focused on identifying the underlying risk-factors for CRC, defining the best endoscopic techniques for surveillance and establishing optimal preventive strategies aimed at reducing CRC-incidence without exposing patients to unnecessary procedures. The purpose of this chapter is to review, from a practical perspective, current knowledge and future directions in the diagnosis and management of serrated polyposis syndrome.

Hyperplastic polyposis associated with two asynchronous colon cancers

We report a patient with hyperplastic polyposis who had two asynchronous colon cancers, a combined adenoma-hyperplastic polyp, a serrated adenoma, and tubular adenomas. Hyperplastic polyposis is thought to be a precancerous lesion; and adenocarcinoma arises from hyperplastic polyposis through the hyperplastic polyp-adenoma-carcinoma sequence. Most polyps in patients with hyperplastic polyposis present as bland-looking hyperplastic polyps, which are regarded as non-neoplastic lesions; however, the risk of malignancy should not be underestimated. In patients with multiple hyperplastic polyps, hyperplastic polyposis should be identified and followed up carefully in order to detect malignant transformation in the early stage.

Effect of Helicobacter pylori eradication on gastric hyperplastic polyposis in Cowden’s disease

A 21-year-old woman with complaints of hematochezia was diagnosed as having Cowden’s disease (CD), an autosomal dominant condition characterized by multiple hamartomas, since facial papules and gingival papillomas were identified. On endoscopy, multiple hyperplastic polyps were seen in the rectum and left-side colon. There were also esophageal glycogenic acanthosis and hyperplastic polyposis in the antrum accompanied by Helicobacter pylori-related gastritis. Although gastric hyperplastic polyposis had by no means regressed with unsuccessful first-line eradication therapy for H pylori, following cure of the infection with salvage therapy consisting of rabeprazole, amoxicillin and metronidazole, the polyposis lesions almost disappeared. Follow-up gastroscopy 2 and 3 years after cessation of the second-line eradication therapy revealed almost complete regression of the polyposis lesions with no evidence of H pylori infection. We recommend eradication treatment for CD patients with gastric hyperplastic polyps and the infection, as the occurrence of gastric carcinoma among hyperplastic polyps has been described.