Characteristic of Mixed Hyperplastic-adenomatous Polyps at Ramathibodi Hospital
Keywords:Mixed hyperplastic-adenomatous polyps, serrated adenoma
AbstractIntroduction: Mixed hyperplastic-adenomatous polyps contain foci of hyperplastic change with dysplastic
adenomatous change. These polyps are likely to be heterogeneous at a molecular level and may predispose to
sporadic colorectal cancer through a distinct pathway. Aim of this study was to describe characteristics of mixed
hyperplastic-adenomatous polyps in Thai patients.
Methods: A retrospective study included 272 polyps from 201 patients detected by colonoscopy in the
General Surgery Unit at Ramathibodi Hospital during the past one year period (Jan-Dec 2007).
Results: There were 141 mixed hyperplastic-adenomatous polyps from 104 patients. There were 63
(60.5%) male and 41 (39.5%) female. The mean age was 62 (21-87 years). Most polyps (63.8%) were in left colon
especially sigmoid colon (29.2%). Size of polyps was ≤0.5 cm in 69%, 0.6-1 cm in 23.8%, 1.1-2.0 cm in 4.7% and
> 2 cm in 2.4%. Morphology of polyps was sessile in 56.8%, pedunculated polyps in 34% and others were flat
polyps (9.2%). All detected polyps were endoscopically removed, which technically failed in 1 patient.
Polypectomy (53.3%) was performed in medium and large size polyps. Hot biopsy (39%) was the main treatment
in small polyps. Of 141 polyps identified, 54.8% of polyps were serrated adenoma. There were severe dysplasia
in 5.7% and carcinoma in situ in 1.4%. Only 0.7% of removed polyps contain adenocarcinoma.
Conclusion: The majority of colorectal polyps at our hospital are small size sessile mixed hyperplasticadenomatous
polyps mainly located in left-sided colon. These polyps should be recognized and endoscopically
removed to decrease risk of subsequent colorectal cancer.
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