Colon Polyps : Anatomic Distribution
Anatomic Distribution of Adenomatous Polyps: Both autopsy series and surveillance colonoscopy in asymptomatic subjects have shown a uniform distribution of adenomatous polyps throughout the colon. In the autopsy series, larger adenomas show a distal predominance, like colon cancer, further supporting adenoma-carcinoma hypothesis. Adenomas detected via surgery or colonoscopy in symptomatic patients show left-sided predominance. In persons older than 60 years, the distribution of adenomas shifts towards more proximal locations in the colon. African-Americans are more likely to have proximal adenomas than whites, especially beyond age 60 years. This specimen shows multiple small tubular adenomas in a colectomy specimen. In patients with multiple adenomas, the greater the number of adenomas, the higher the percentage of cases with high-grade dysplasia or carcinoma.