Читать книгу Gastrointestinal Pathology - Группа авторов - Страница 22

Increasingly, endoscopic resection methods are being applied to early neoplasia the esophagus, particularly Barrett's esophagus and early squamous cell carcinoma. These are largely confined to tumors suspected to be T1 or nodular high‐grade dysplasia. Endoscopic mucosal resection (EMR) methods generally involve an EMR device such as a modified band ligator followed by snare resection of the pseudopolyp (Figure 1.11–1.13).

Other methods include endoscopic submucosal dissection (ESD) in which the lateral margins of the suspected area are incised with electrocautery knife followed by dissection along the submucosal plane to obtain an en bloc specimen. EMR devices can typically obtain samples 1–2 cm in diameter into the depth of the mid‐submucosa. Endoscopic submucosal dissection can obtain samples of any lateral diameter and generally to the base of the submucosa.

Figure 1.11 Barrett's esophagus with flat neoplasia (9 o'clock) for targeted endoscopic resection.

Figure 1.12 Multiband mucosectomy device. The black rubber bands are mounted on the outside of a plastic cap. The tissue is suctioned into the cap and a band deployed to create a pseudopolyp, which is then removed by snare.

Figure 1.13 Area of resection at 6–12 o'clock includes the entire region of suspected neoplasia at 9 o'clock. The remaining tissue at the 9 o'clock area represents intact deep submucosa and muscularis propria.

One major advantage of these techniques is the ability to perform wide‐field or en bloc resection and orient the sample. Samples should be retrieved without causing trauma to the tissue, preferably by removal through the endoscopic cap or through a snare‐net as opposed to suctioning via the accessory channel, which can traumatize or fragment the tissue. Once retrieved the tissue should be handled as with other endoscopic resection specimens by orienting the specimen and pinning it on a fixed material such as a paraffin block. En bloc specimens can be oriented in terms of the oral and anal side of the lesion and assessed for lateral and deep margins. For resections that are performed piecemeal such as with multiband mucosectomy, the lateral margins cannot be accurately assessed and so complete resection relies on the endoscopic inspection intraluminally. The specimens should still be oriented and assessed for the deep margin.