Polyps Detected by CT Colonography: A Histologic Review
JD Kemp, PE Young, BD Cash, SM Hussey. National Naval Medical Center, Bethesda, MD; National Naval Medical Center and Uniformed Services University of Health Sciences, Bethesda, MD
Background: Computed tomographic colonography (CTC) is a minimally-invasive diagnostic modality comparable to the gold standard colonoscopy for the detection of neoplastic colonic lesions in asymptomatic patients. Though it has been widely endorsed as a screening tool for colorectal cancer (CRC), little information exists on the radiologic-histologic correlation of polyps discovered by CTC. Our study aims to address this by reviewing the histopathology of these polyps.
Design: Asymptomatic, average-risk patients referred for colon cancer screening underwent CTC and were categorized into two groups based on the findings. Patients with polyps > 10 mm or with > 3 polyps exceeding 6 mm were referred for immediate clearing optical colonoscopy (OC) and all polyps were biopsied (Category A). Patients with 1 or 2 polyps measuring 6-9.9 mm had follow-up CTC and clearing OC at 1 year (Category B). All biopsies from patients in both categories from 2004-2009 were reviewed retrospectively by a pathologist (SH). Patient demographic information was reviewed using the electronic chart system.
Results: Category A included 40 patients (28% female, 72% male) with a mean age of 57 years and a total of 109 polyps (2.7 polyps per patient). 84 polyps (77%) were adenomatous, including 69 tubular adenomas (TA), 13 tubulovillous adenomas (TVA), and 2 sessile serrated adenomas (SSA). Six of these (4 TAs and 2 TVAs) contained foci of high grade dysplasia. Another 23 polyps (21%) were non-adenomatous, including 19 hyperplastic polyps (HP), 1 carcinoid tumor, 1 juvenile polyp, 1 inflammatory polyp, and 1 lipoma. 2 cases of colonic adenocarcinoma (2%) were identified. Category B included 60 patients (23% female, 76% male) with a mean age of 57 years and a total of 124 polyps (2.1 polyps per patient). 96 polyps (77%) were adenomatous, including 90 TAs, 4 TVAs, 1 villous adenoma (VA), and 1 SSA. 1 TA contained high grade dysplasia. 28 polyps (23%) were non-adenomatous (26 HPs, 2 inflammatory polyps). There were no malignancies identified in Category B.
Conclusions: Our findings correlate with previous studies in identifying rates of adenomatous change, "advanced histology" (high grade dysplasia and/or villous architecture) and invasive carcinoma in polyps found at OC. Advanced histology was seen more commonly in polyps greater than 10 mm. Observation for one year in patients with polyps between 6 and 9.9 mm did not result in increased rates of dysplasia or neoplasia.
Monday, March 22, 2010 9:30 AM
Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 93, Monday Morning