title: Pseudoinvasion in an adenomatous polyp of the colon mimicking invasive colon cancer.
abstract: Pseudoinvasion or pseudocarcinomatous invasion in an adenomatous polyp of the colon can be unfamiliar to an endoscopist. Pseudoinvasion in an adenomatous polyp represents prolapse of the adenomatous epithelium into its stalk. In most cases its morphology does not differ from of general adenomatous polyps, but in some cases it can morphologically mimic a malignant polyp with submucosal invasion due to mass-like lesioning of its stalk. This makes it difficult for endoscopists to differentiate pseudoinvasion in an adenoma from an invasive carcinoma by conventional endoscopy; instead, endoscopic ultrasonography can provide useful information for differentiating these conditions. We report on an 82-year-old man who presented with a large pedunculated polyp with a thick stalk in the sigmoid colon, which mimicked a submucosal invasive carcinoma. The patient was diagnosed with pseudoinvasion in an adenomatous polyp after segmental resection of the sigmoid colon.
authors.affiliation: Department of Gastroenterology, Hanyang University College of Medicine, Guri Hospital, Guri, Korea.
authors.forename: Tae Jun
authors.initials: TJ
authors.lastname: Byun
authors.forename: Dong Soo
authors.initials: DS
authors.lastname: Han
authors.forename: Sang Bong
authors.initials: SB
authors.lastname: Ahn
authors.forename: Hyun Seok
authors.initials: HS
authors.lastname: Cho
authors.forename: Chang Soo
authors.initials: CS
authors.lastname: Eun
authors.forename: Yong Cheol
authors.initials: YC
authors.lastname: Jeon
authors.forename: Joo Hyun
authors.initials: JH
authors.lastname: Sohn
authors.forename: Young-Ha
authors.initials: YH
authors.lastname: Oh