结肠镜检查的内窥镜切除直肠肿块

Colonoscopy of Endoscopic Resection of a Rectal Mass

Colonoscopy of Endoscopic Resection of a Rectal Mass
Tubulovillous Adenoma with high-grade dysplasia

This is a 75 year-old female, was referred to our endoscopic unit to evaluate a rectal
mass.

Polyps of the colon are mucosal lesions which project into the lumen of the bowel. According to autopsy studies, colonic polyps occur in more than 30% of people over the age of 60. Approximately 70-80% of resected polyps are adenomatous. Adenomatous lesions have a well-documented relationship to colorectal cancer. This adenoma-carcinoma progression represents a significant public health problem, since colorectal cancer is the second leading cause of cancerspecific mortality in the United States. Therefore, appropriate management of colonic polyps may reduce the risk of death from colorectal cancer.

Types of Polyps

There are four types of colonic polyps: adenomatous, hyperplastic, harmartomatous and inflammatory. In addition to these histologic features, polyps are generally described as being either sessile (flat) or pedunculated (having a stalk). Inflammatory and small hyperplastic polyps do not have malignant potential and therefore do not require any further intervention and should not alter surveillance intervals. While most harmotomatous polyps do not have malignant potential, those associated with Peutz-Jeghers syndrome and juvenile polyposis do contain a risk for malignant transformation and therefore require more aggressive intervention and monitoring. Adenomatous polyps are considered precursors for invasive colon and rectal cancer. Histologically these polyps are either villous, tubular or tubulovillous. The risk of malignancy increases with both the size of the polyp and the degree of villous component.

Adenomatous polyps are common neoplastic
lesions of the large intestine. The risk of carcinoma
increases with polyp size. Small polyps are typically
totally embedded for histologic examination, but no
standard method for sampling large, grossly benign
polyps has been established.

Colonic polyps are common specimens encountered in a
pathology practice. It is well established that adenomas
represent precursor lesions to invasive colonic carcinoma.
This is supported by the presence of a spectrum of histologic
changes in adenomas that range from low-grade dysplasia to
frankly invasive carcinoma.
When high-grade dysplasia is
present, there is a strong association with the presence of
invasive carcinoma, and once carcinoma is invasive into
the submucosa, there is a 14% risk for metastasis.

Colonoscopy is the most accurate method for detection of polyps and is the first-line procedure of choice. The sensitivity for detecting polyps by colonoscopy compared to double-contrast barium enema is 94% and 67%, respectively. Although accuracy is operator-dependent, colonoscopy is regarded as the criterion standard.

Cautery snare is recommended for removal of larger polyps. For large sessile polyps, for which the risk of perforation is higher, injection of 1 mL or more of saline into the submucosa directly under the polyp is a useful technique. This lifts the flat polyp away from the muscular layer, creating a stalklike effect. A couple of drops of methylene blue added to the saline also allows the operator to determine if a perforation has occurred in the muscle layer, which would be seen as a break in the layer. Smaller sessile polyps should be removed or biopsied and ablated with hot-biopsy forceps or a minisnare.
After removal of a large (2 cm) sessile polyp or if the possibility exists of incomplete removal of a large adenoma, a follow-up colonoscopy usually should be performed within 3-4 months.



结肠镜检查内窥镜切除直肠
绒毛状腺瘤质量高档异型增生，这是一个75岁的女性，被称为内镜单位评估直肠肿块。结肠息肉黏膜病变管腔的项目进入排便。根据尸检，结肠息肉发生在超过30％的60岁以上的人。约70-80％的手术切除息肉均为腺瘤。腺瘤病变有记录的大肠癌的关系。这腺瘤癌的进展代表一个重大的公共健康问题，因为大肠癌的死亡率在美国cancerspecific的第二大原因。因此，适当的管理，结肠息肉可减少大肠癌死亡的风险。息肉的类型有四种类型的结肠息肉：腺瘤，增生harmartomatous的炎症。除这些组织学特征，息肉一般描述为任一无梗（平面）或有蒂（具有一个柄）。炎症性和小的增生性息肉没有恶变的可能，因此不需要任何进一步的干预和监视的时间间隔不应改变。虽然大多数harmotomatous的息肉没有恶变的可能，黑斑息肉综合征，幼年性息肉伴有包含恶变的风险，因此需要更积极的干预和监测。腺瘤性息肉被认为是浸润性结肠癌和直肠癌的前体。组织学上，这些息肉或绒毛状，管状或绒毛状。恶性肿瘤的风险增加大小的息肉，绒毛状成分的程度。大肠腺瘤性息肉是常见的肿瘤性病变。癌的风险增加息肉的大小。小息肉通常用于组织学检查，完全嵌入，但是没有标准的方法进行采样大，严重良性息肉已建立结肠息肉病理实践中遇到的常见样品。这是公认的腺瘤浸润性结肠癌的癌前病变，这是支持的存在腺瘤的组织学变化的频谱范围从低度不典型增生到浸润癌坦言，当高档异型增生目前，浸润性癌的存在很强的关联，而一旦肿瘤侵入到粘膜下层，有14％的风险转移。结肠镜检查是最准确的方法检测息肉和选择的是第一线的程序。相比双对比钡灌肠结肠镜检查息肉检测的灵敏度分别为94％和67％。虽然精度取决于运营商，结肠镜检查被视为标准的标准，建议去除较大的息肉烧灼网罗。对于大型无蒂息肉，穿孔的风险较高，注射1毫升或更多的生理盐水进入粘膜下层，直属息肉是一个非常有用的技术。这升降机扁平息肉远离肌层，创建stalklike效果。亚甲基蓝的一对夫妇的滴加入生理盐水还允许操作员在肌肉层，在该层中的中断将被视为以确定是否已发生穿孔。较小的无蒂息肉应被删除或活检和消融热活检钳或minisnare的的。搬迁后的大（2厘米）的无蒂息肉或不完全切除的大腺瘤的可能性是存在的，后续的结肠镜检查通常应3-4个月内进行。

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