Colon Polyps : Treatment - 2

Comments:
Colonic polyps are usually treated by polypectomy when detected during routine surveillance colonoscopy. A small biopsy from a large polyp cannot rule out carcinoma due to sampling; therefore, polyps should be removed completely and intact. This allows proper orientation of the specimen and assessment of margins which becomes important if carcinoma is present. It would help decide whether additional surgery is required. A close communication among endoscopist, surgeon, and pathologist is crucial if there are any questions about specimen orientation.

Larger polyps may require piecemeal excision. Repeat colonoscopy is recommended in 3 to 6 months to document completeness of excision. If a large polyp cannot be completely excised in 2 or 3 endoscopic sessions, surgical excision of the bowel segment may be required.

Polyps with carcinoma confined to the muscularis mucosae and/or lamina propria are considered pTis. When removed by endoscopy with clear margins, they are considered cured and lymph node dissection is not warranted.

Pedunculated colorectal polyps with invasive carcinoma (extending beyond muscularis mucosae into submucosa) are classified as pT1 tumors and considered adequately treated by endoscopic polypectomy if: 1) the tumor is well- or moderately-differentiated; 2) lacks lymphovascular invasion and 3) has at least 1mm negative surgical margin. The adequacy of excision may be difficult to assess in fragmented specimens and such cases may require bowel resection. In sessile adenomas, submucosal invasion is an adverse pathologic feature and warrants surgical excision.

This whole slide scan shows invasive mucinous adenocarcinoma arising in a tubular adenoma. The submucosa contains pools of mucin within which were strips of well-differentiated malignant glands (see next two images).