title: Colorectal villous adenoma: transrectal US in screening for invasive malignancy.
abstract: Exclusion of focal infiltrating malignancy in colorectal villous adenoma is a prerequisite when nonsurgical treatment is considered. In a study of 81 patients with endoscopically identified colorectal villous adenoma screened for malignancy with transrectal ultrasonography (US), 15 patients were excluded because of incomplete follow-up. Twelve carcinomas were present, confirmed with either histopathologic examination after surgical resection (n = 9) or biopsies during laser treatment (n = 3). Nine of them were detected with transrectal US on the basis of disruption of the anatomic wall layers (sensitivity, 75%). In 46 of the 54 adenomas transrectal US helped confirm the benign nature of the lesion (specificity, 85%). Seven of the eight false-positive cases happened to be previously treated with surgery or coagulation. Treatment-associated inflammatory changes in the wall layers seemed responsible for this misinterpretation. Because of the high predictive value for a negative result (benign adenoma, 94%), transrectal US is recommended for the evaluation of villous adenomas to detect malignancy, especially when nonsurgical treatment is considered. Transrectal US should be performed before diagnostic polypectomy.
authors.affiliation: Department of Radiology, Academic Medical Center, Amsterdam, The Netherlands.
authors.forename: F H
authors.initials: FH
authors.lastname: Hulsmans
authors.forename: T L
authors.initials: TL
authors.lastname: Tio
authors.forename: E M
authors.initials: EM
authors.lastname: Mathus-Vliegen
authors.forename: A
authors.initials: A
authors.lastname: Bosma
authors.forename: G N
authors.initials: GN
authors.lastname: Tytgat
mesh_terms: D000236:Adenoma / Q000000981:diagnostic imaging*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003110:Colonic Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D006801:Humans; D008722:Methods; D008875:Middle Aged; D012004:Rectal Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D014463:Ultrasonography