Sessile Serrated Adenomas: A Case PresentationKevin Witt, PGY3Justin Whitt, MDIU Health Ball Memorial Family Medicine Residency

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Introduction• Sessile serrated adenomas (SSAs) of the colon are a

challenging entity in colon cancer screening due to subtle morphological features.

• Endoscopic differentiation between SSAs and more benign lesions is difficult.

• SSAs are also more common than benign traditional serrated adenomas (TSAs) and are premalignant1.

• Endoscopic recognition of these lesions is important for effective colon cancer screening and prevention.

Case• A 52 year-old male with no family history of colon cancer presented

for routine screening by colonoscopy.• Procedure performed via routine, cecum successfully identified.• An Olympus 160L Model Colonoscopy was used (no narrow or

high-band imaging)• An irregular fold without mucosal irregularity in the hepatic flexure

was identified and a biopsy was obtained.• A 7x9mm adenomatous-appearing polyp was identified and

removed from the distal transverse colon. • Pathologic analysis demonstrated sessile serrated features of both

lesions (the irregular fold at the hepatic flexure and the polyp); however the polyp demonstrated features of high-grade dysplasia.

Case f/u Due to the uncertainty in size of the lesion at the hepatic

flexure, and the polyp with SSA/HGD, the pt was categorized as high risk for colon cancer.

After discussion w/ the pt, he was ultimately referred to GI for evaluation.

Repeat colonoscopy was performed w/ multiple polyps/polypectomy 4x polypectomies performed. The largest was 15mm at the

hepatic flexure The 15 mm polyp showed SSA features w/out high grade

dysplasia The remainder (3-4 mm polyps) were tubular adenomas

Repeat colonoscopy in 1 year was recommended due to number of polyps and previous SSA w/ high grade dysplasia

Endoscopic Features of SSAs1,2

• Pale Color• Flat or sessile shape• Indistinct edges• Mucus cap• Debris on edges or center• No surface vessels/few lacy vessels• Surface texture and pits vary from normal• Type “O” Pits

Discussion• Detection and removal of precancerous lesions on

screening colonoscopy is key in colon cancer prevention. • SSAs can be insidious and difficult to detect with basic

optical colonoscopy.• Histologic diagnosis of SSA is also difficult. Accurate

diagnosis of SSA and TSA was the lowest among all categories tested5.

Conclusion• Sessile serrated adenomas account for one-third of all

sporadic colorectal cancers and are the main precursor lesion in serrated carcinogenesis.

• Perhaps advanced imaging, such as narrow-band or hi-definition optics, during colonoscopy should be more commonly utilized in order to better identify these precancerous lesions.

References1. Rex DK, Ahnen DJ, Baron JA, et al. Serrated lesions of the colorectum: review and

recommendations from an expert panel. Am J Gastroenterol 2012;107:1315-292. Hazewinkel Y, Lopez-Ceron M, East JE, et al. Endoscopic features of sessile serrated

adenomas: validation by internation experts using high-resolution white-light endoscopy and narrow-band imaging. Gastrointest Endosc 2013;77:916-24.

3. Sanak MR, Gohel T, Podugu A, Kiran RP, Thota PN, Lopez R, Church JM, Burke CA. Adenoma and sessile serrated polyp detection rates: variation by patient sex and colonic segment but not specialty of the endoscopist. Dis Colon Rectum 2014;57(9):1113-9

4. Uraoak T, Higashi R, Horii J, Harada K, Hori K, Okada H, Mizuno M, Tomoda J, Ohara N, Tanaka T, Chiu HM, Yahagi N, Yamamoto K. Prospective evaluation of endoscopic criteria characteristic of sessile serrated adenomas/polyps. J Gastroenterol 2014

5. Glatz K, Pritt B, Glatz D, Hartman A, O’Brien MJ, Blazyk H. A multinational, internet-based assessment of observer variability in the diagnosis of serrated colorectal polyps. Am J Clin Pathol 2007;127:938-945