[626] Hyperplastic Polyposis Syndrome Is an Underdiagnosed & Unclear Entity: An Opportunity for the Surgical Pathologist?

CD Crowder, K Sweet, AM Bellizzi, WL Frankel. Ohio State University, Columbus, OH; Brigham & Women's Hospital, Boston, MA

Background: Hyperplastic polyposis syndrome (HPS) is poorly defined and has an increased but unclear risk of colorectal carcinoma (CRC). Its clinical importance relates to its frequent association with the serrated pathway to CRC, characterized by BRAF mutations, CpG island methylation and CRC with microsatellite instability. We determined the frequency of HPS in individuals in whom serrated polyps (SPs) were detected at colonoscopy, and assessed whether surgical pathologists can help identify those at risk of HPS during routine sign out.
Design: We reviewed pathology reports with a diagnosis of hyperplastic polyp (HP) or sessile serrated adenoma (SSA) within a large, university centered system over a 6 month period. Previous pathology reports (routinely available during sign out) were reviewed, and current and total number of polyps and polyp types were recorded. For individuals with ≥ 5 cumulative SPs, endoscopy reports were reviewed for polyp number, size and location. We determined which individuals met current WHO criteria for HPS.
Results: 951 cases with a diagnosis of HP or SSA were identified. Of these, 124 had ≥ 5 cumulative SPs, prompting review of endoscopy reports. 17 (1.8 %) met WHO criteria. This group included 7 men and 10 women, with an average age of 59.1 years. 14 cases met WHO criteria of ≥ 5 proximal SPs, 2 of which are > 1.0 cm; 1 met the criteria of ≥ 30 SPs distributed throughout the colon; and 2 met both criteria. Among this group, mean cumulative SP count was 18.9 (total) and 13.4 (proximal to sigmoid); the mean SP in the current colonoscopy was 4.1. Nine (52.9%) of these individuals had ≥ 3 SPs detected at the current colonoscopy. 2 additional individuals (50 and 78 years) did not fulfill criteria but had > 25 cumulative SPs throughout the colon.
Conclusions: HPS is rare but likely underdiagnosed (17 patients met WHO criteria in a 6 month review). No threshold number of SPs in a single endoscopy was clearly useful to flag those most at risk for HPS. However, if a cut-off of 3 SPs at 1 colonoscopy was chosen, > 50% would have been identified. Additional studies to address the underlying genetic basis for HPS are ongoing in order to further illuminate this ambiguous syndrome. Surgical pathologists, especially those with access to prior pathology reports at the time of routine sign out, are in a unique position to assist in this endeavor by identifying those patients who either meet or appear at high risk to meet WHO criteria.
Category: Gastrointestinal

Monday, March 22, 2010 9:30 AM

Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 91, Monday Morning


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