Intestinal polyposis

Introduction to intestinal polyposis Polypofintestinaltract is a general term for all neoplastics that protrude into the lumen of the intestine, including both neoplastic and non-neoplastic. basic knowledge Probability ratio: patients with a family history have an incidence of up to 40% Susceptible people: no specific people Mode of infection: non-infectious Complications: anemia

Causes of intestinal polyposis

Histological features of colorectal adenomas (25%):

The histological features of colorectal adenomas are not only the histological basis of adenoma classification, but also the basis for the diagnosis of adenomas. Adenomas are divided into tubular adenomas, villous adenomas, mixed adenomas (ie tubular villus adenomas). The histological section of the adenoma often shows a villous component, which is a plurality of slender branches protruding from the base of the lesion. It is rich in mucus secretion. The cord core is composed of loose fibrous connective tissue, and the surface is covered with a single layer or a multi-layer column. Epithelial cells, the amount of villus components is positively correlated with the malignancy of adenomas. Therefore, correct evaluation of the amount of villus contained in adenomas is helpful for judging the malignant potential. It should be understood that the distribution of villus components in different parts of the same adenoma is different. The pathological diagnosis of the tissue taken at different sites may be different.

Histologically, the tubular adenoma was only seen in the early stage of crypts, which were densely arranged by high columnar cells. The nuclear staining was deep, the goblet cells were reduced, and disappeared. The progression of the lesions showed obvious hyperplasia of the glandular vessels, prolongation, branching, dilatation, glandular size, epithelium. Cell proliferation, protruding into the cavity, has a tendency to form nipples; nuclear staining, a small number of nuclear division, but located in the basal, interstitial with a small amount of connective tissue, small blood vessels and inflammatory cells infiltration, unlike tubular adenoma, villous gland Tumors usually occur from the surface epithelium of the large intestine mucosa and grow into the intestinal lumen to form a papillary mass. The histology is a typical slender villous structure. The villi are often directly connected to the mucosal surface. There are single or multi-layered columnar epithelial cells on the surface. The unequal, arranging rules, the nuclear staining is located on the basal, the mitotic figures are more common, the cord core of the villi is composed of fibrous connective tissue, containing unequal small blood vessels and inflammatory cell infiltration, and the mixed adenoma is histologically tubular adenoma. Foundation, mixed with villous adenoma components.

Colorectal adenoma carcinogenesis (20%):

Adenoma carcinogenesis is characterized by nuclear abnormalities, loss of polarity, increased proportion of nucleoplasm and a large number of mitotic figures. According to the depth of invasion, it can be divided into carcinoma in situ and invasive carcinoma. The two are based on the mucosal muscle layer. Therefore, no metastasis is due to the absence of lymphatic vessels in the lamina propria of the intestinal mucosa. Therefore, the clinically described adenoma cancer is often directed at invasive cancer. The vast majority of colorectal cancers are cancerous from colorectal adenomas, affecting the carcinogenesis of adenomas. The main factors are the degree of atypical hyperplasia, the enlargement of adenoma and the degree of hyperplasia of villus. The enlargement of adenoma and the increase of villus content can aggravate the degree of atypical hyperplasia of cells. Adenomas with a diameter of less than 1 cm rarely undergo carcinogenesis, and tubular adenomas become cancerous. The rate is low, and the carcinogenic rate of villous adenoma is about 5 times higher than that of tubular adenoma.

Familial multiple adenoma (20%):

The disease is an autosomal dominant hereditary disease. Endoscopic features are a large number of small adenomas, most of which are only a few millimeters in size, a few more than 1 cm in size, morphologically sessile and semi-annular, nodular bulge, smooth surface or It is lobulated, with red color and soft, pedunculated or pedunculated. Intensive people have carpet-like structure, histologically the same as adenoma, rare hyperplastic polyps, but the incidence of cancer is high, and the cancer is terminated within 5 to 20 years. It will occur, the average age of canceration is 39 years old, and it is more common in multiple centers.

Turcot syndrome (15%):

The disease is characterized by multiple colorectal adenoma and central nervous system malignant tumor, which is autosomal recessive. Unlike familial adenoma, the adenoma is also distributed in the whole large intestine, but the number is small, scattered, 10 There are rarely more than 100 in the age, more than 100 in the age of 10, and the age of cancer is early, usually under 20, more common in women.

Gardner syndrome (10%):

4 kinds of lesions:

(1) multiple adenomas in the large intestine.

(2) osteoma (prone to the humerus, skull and long bones).

(3) Hard fibroma (prone to the mesentery after surgery).

(4) skin tumors (including sebaceous cysts and epithelioid cysts, mostly in the back of the head, face and limbs, and some visible tooth deformities).

Some of the above lesions appear to be completely type, such as the latter three lesions appear two incomplete, only one is simple, generally considered hereditary, age of onset, number, type, distribution of colorectal adenoma, The chance of canceration is the same as that of the general familial adenoma. Clinically, compared with familial adenoma, the age of onset of colorectal adenoma is later, and the number of adenomas may be less after the symptoms of digestive tract.

Peutz-Jephers syndrome, also known as hamartomatous polyposis, is an autosomal dominant inheritance, but only half of the clinical family history is characterized by multiple gastrointestinal polyps; hereditary; specific parts Melanin spots appear on the skin and mucous membranes. The black spots occur in the skin around the lips and on the cheek mucosa. The edges are clear and the diameter is about 1-2 mm. The histology is the increase in the number of melanocytes in the dermis and the melanin deposition. Most of the polyps exceed 100. It is more common in the small intestine (64% to 96%) and 30% to 50% in the large intestine. This disease can also be cancerous.

There are many classification methods for colorectal polyps. According to the number of polyps, it can be divided into single and multiple. However, it is widely used at home and abroad based on Morson's histological classification, which divides colorectal polyps into tumor, hamartoma, inflammation. Sexuality and hyperplasia, the biggest advantage of this classification is that the colorectal polyps are collectively called adenomas, while other non-neoplastic polyps are collectively called polyps, which evolve into adenomas. This classification can clearly distinguish the pathological properties of colorectal polyps. It has greater guiding significance.

Domestic reports of adenomatous polyps are the most common, while foreign countries have reported that hyperplastic polyps are the most common, the incidence rate is as high as 25% to 80%; the incidence of hyperplastic polyps in adults is at least 10 times higher than that of adenomas, but some scholars In the colonoscopy, the incidence of adenoma was found to be three times that of hyperplastic polyps. According to the research data, the occurrence of polyps may be mainly seen in the distal colon. This can be seen from the autopsy material. It has been verified for many reasons that polyps gradually develop from the left side to the right side with age.

The tissue of adenoma is not well understood. The initial study showed that the deep crypt cells gradually migrated with the migration to the surface. The deep epithelium of the normal crypt is mainly expressed by sulfuric acid mucus, while the adenomatous epithelial sulfate Mucus is more than sialic acid mucus. Recent studies have shown that bloody Ley antigen is diffusely stained in many adenomas, while positive mucosa is only found in deep crypts. The consistency of these adenoma epithelium and deep ectopic histochemistry Strong support for the possibility of adenoma originating in the deep part of the crypt. Another hypothesis of the origin of adenoma is the eosinophilic epithelium, which is often located near the adenoma epithelium, and sees the migration of both, in the colorectal adenoma colorectal cancer sequential theory On the basis of the existence of normal large intestinal mucosa tubular adenoma tubular villus adenoma villous adenoma colorectal cancer sequential phenomenon, it is believed that the initial occurrence of adenoma is mostly tubular adenoma, and then gradually to tubular villus adenoma and villus adenoma Transformation, and finally evolved into colorectal cancer, and cancerous at the stage of tubular adenoma and tubular villus adenoma.

Regardless of the location of the adenoma, which is located in the crypt, the adenoma tissue hyperplasia is mainly to form a protruding mass toward the luminal surface, although all adenomas are initially broad-type growth, but with adenoma When it becomes larger, some adenomas become pedicle or yttrium. In the descending colon and sigmoid colon, due to strong intestinal peristalsis, feces are formed, and pedicled polyps are more likely to form here than other parts of the intestine.

Intestinal polyposis prevention

In recent years, studies have reported that long-term oral sulindac and other non-steroidal anti-inflammatory drugs have the effect of preventing the recurrence of polyps, but attention should be paid to other side effects of the drug. At the same time, the effect of this preventive treatment remains to be seen in large cases.

Intestinal polyposis complications Complications anemia

Weight loss, anemia is its main complication.

Intestinal polyposis symptoms Common symptoms Abdominal discomfort, bloody irritable bowel syndrome, weight loss, colon polyps, intestinal bleeding, bowel habits, change of abdominal pain, loose stools

Most of the colorectal adenomatous polyps are insidious, without any clinical symptoms. A few manifestations are changes in bowel habits, blood and mucus in the stool, increased stools, increased frequency, and varying degrees of abdominal discomfort, occasional abdominal pain, weight loss, anemia, etc. Systemic symptoms, very few stools have a mass from the anus. Cases with a family history often have a suggestive effect on the diagnosis of polyps. Some typical extraintestinal symptoms often suggest polyps. Some patients often see symptoms due to extraintestinal symptoms. , can not be ignored, because the disease has few clinical symptoms, easy to ignore or missed diagnosis, therefore, the diagnosis of colon polyps must first improve the understanding of the disease, any unexplained blood in the stool or gastrointestinal symptoms, especially in the middle of 40 years old Older men should be considered for further examination to improve the rate of diagnosis and diagnosis of colorectal polyps.

Intestinal polyposis examination

1. Fecal occult blood test: its diagnostic significance is limited, more false negatives, positive can provide clues for further examination.

2. X-ray examination: X-ray barium enema can detect the colorectal polyps sensitively through the filling defect of the tincture, but the lesions are often not correctly classified and characterized.

3. Endoscopy: Endoscopy can not only observe the microscopic lesions of the large intestine mucosa under direct vision, but also determine the nature of the lesion through tissue biopsy and cytology brush examination, so it is the most important means to detect and diagnose colorectal polyps. The polyps found by endoscopy should be biopsied to understand the nature, type and presence of polyps of the polyps. Small or pedicled polyps can be removed by biopsy forceps or snares. Large or broad-based Large polyps often only take biopsy. Because the disease has a high incidence in the population, it is occasionally found in colon cancer screening or further examination of patients with gastrointestinal discomfort, if colonoscopy is found Polyps less than 1cm in diameter usually require biopsy and then further treatment according to pathological results; if it is a polyp larger than 1cm in diameter, no biopsy is needed, and the polyp is performed directly under the colonoscopy; if the polyp is found under sigmoidoscopy, and the biopsy is confirmed For adenomas, colonoscopy is required for further examination to rule out other adenomas or neoplastic lesions that may be present in the proximal colon.

Because the amount of villous components and the degree of dysplasia in different parts of the same adenoma are different, the lesions in the biopsy can not fully represent the whole appearance. There is no cancer in the biopsy. It is not certain that the adenoma is cancerous, so the adenoma The degree of atypical hyperplasia and non-cancerous changes often require the removal of the entire tumor. After careful biopsy, it is certain that the pathological results of biopsy can be used for reference, but it is not the final conclusion. The results of this preoperative biopsy and postoperative biopsy The pathological diagnosis is quite common in villous adenomas.

Diagnosis and differential diagnosis of intestinal polyposis

Diagnostic criteria

1. Clinical manifestations. 2. X-ray inspection. 3. Endoscopy.

There are three ways to detect polyps. The most common ones are patients who are found by chance of bowel dysfunction (such as irritable bowel syndrome) or rectal bleeding. The second type is found in the asymptomatic population survey. The three types of polyps are large, and the patients are diagnosed with polyps due to the symptoms of blood in the stool or polyps. Since there are no clinical signs of polyps, the polyps found through the third route are very limited.

Differential diagnosis

Adenoma is a protrusion of the large intestinal mucosal epithelial tissue to the intestine. The appearance is slightly red, which can be distinguished from the gray-white hyperplastic polyps, but even an experienced endoscopic doctor does not exceed 70%. Adenomas below 0.5 cm or hyperplastic polyps >0.5 cm are highly susceptible to misdiagnosis.

1. Tubular adenoma Most adenomas are tubular adenomas, which occur in the rectum and sigmoid colon. They are more common, accounting for 85%, ranging from a few millimeters to 10 cm. Adenomas with a diameter of 1 to 2 cm are more common. The shape of adenoma is mostly spherical or hemispherical, the surface is smooth, there may be shallow fissures, obvious congestion, redness, some spotted hemorrhage, forming a tabby-like structure. When there is secondary infection, the surface is accompanied by mucopurulent secretions. 5% to 10% of tubular adenomas are adjacent to the mucosa around the pedicle, and even white spots can appear in the mucosa of the adenoma. The leukoplakia is punctate, clustered and distributed, and the histological changes are mainly inflammation.

2. Villus adenocarcinoma occurs in adults over 50 years old, less common, more common in the left colon, of which rectum accounts for about 82%, sigmoid colon accounts for about 13%, right colon is rare, texture is brittle, often accompanied Erosive bleeding, generally larger than 2cm in diameter, larger than tubular adenoma, and gradually increased with age; surface is not smooth, there are numerous fine villi-like protrusions, often with a lot of mucus; most are no pedicle and yati, there are The pedigree only accounts for 17%, the shape is irregular, the pedestal is flower-like or cauliflower-like, Yati is pompom, and the pedicle is similar to a bunch of grapes.

3. Mixed adenoma is similar to tubular adenoma, with pedicle, more than Yatti, the surface is not smooth, there may be deep fissures, lobulated, with many villous processes.

4. The main symptoms of familial multiple adenoma are blood and mucus in the stool, intestinal obstruction often occurs in cancer, and there are asymptomatic. The prominent feature of familial adenoma is multiple adenoma of the large intestine. The number is more than 100. The adenoma is distributed in the left colon, especially in the sigmoid colon, and the rectum is the most. Under the X-ray, there is a nearly uniform circular filling loss in the whole large intestine. The diameter is 0.3-0.5 cm, and the contour is smooth. In the dense polyp, The double contrast of gas sputum is very similar to the corn-like arrangement, but the traditional tincture enema is easily overwhelmed by the expectorant.

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