FINDINGS AND TREATMENT
Figure 9 – In this photograph, a snare is positioned around a diminutive polyp. The snare can now be retracted into the white plastic sheath, cutting the polyp off. It is also possible to apply electrocautery through the snare while cutting the polyp, although cautery is not necessary for diminutive lesions such as this.
Small adenomas. Diminutive adenomas, less than 5 mm in diameter, are the most common. These are usually easily removed using either a biopsy forceps or a snare. Many experts now favor using a snare without cautery for diminutive lesions (Figure 9).
Large adenomas. Larger polyps, which can be sessile or pedunculated, are usually removed using a snare with monopolar cautery. The snare is positioned around the lesion and then retracted into a plastic sheath while monopolar cautery is applied (electric current travels through the snare to a grounding pad applied to the patient’s buttock or back). The current helps the snare cut through the tissue and also ensures some destruction of adenomatous cells at the resection margin. More advanced techniques are also widely used; these include clip application to prevent bleeding and submucosal saline injection to separate the lesion from the underlying muscle of the colon wall before resection. Since not all endoscopists are experienced in these techniques, patients may be referred to specialty centers for resection.
Nonadenomatous polyps. These are also frequently found in the colon. In the rectum and sigmoid, diminutive hyperplastic polyps are exceedingly common (Figure 10). These lesions have no malignant potential. Adenomatous polyps are usually redder than hyperplastic polyps and typically have a surface appearance reminiscent of brain, with sulci and gyri (see Figure 5).
Figure 10 – A diminutive hyperplastic polyp is seen slightly to the left of the center of this image. It is slightly paler than the surrounding normal mucosa and contains numerous circular crypts, indicating that it is hyperplastic rather than a precancerous adenoma
Carcinomas. Colorectal adenocarcinomas are usually obvious, appearing as large masses (often several centimeters in diameter) that frequently have an ulcerated surface. Multiple forceps biopsies are generally performed to facilitate tissue diagnosis before surgery. More unusual malignancies, such as lymphomas, can also be diagnosed with forceps biopsies. Rarely, infectious ulcers, Crohn disease, or ischemia can have the appearance of an ulcerated mass; in this setting, the tissue samples obtained on biopsy do not demonstrate malignancy. Other findings. These include diverticula, colitis, arteriovenous malformations, and surgical anastomoses.