Colorectal adenoma

Introduction to colorectal adenoma Colorectal adenoma is closely related to colorectal cancer. At present, at least 80% of colorectal cancer is evolved from colorectal adenoma, which lasts for more than 5 years, with an average of 10 to 15 years. Active diagnosis and treatment of colorectal adenoma is to control and reduce colorectal cancer. Important way. basic knowledge The proportion of illness: the incidence rate is about 0.015% - 0.02% Susceptible people: no specific people Mode of infection: non-infectious Complications: Intussusception Intestinal obstruction

Causes of colorectal adenoma

(1) Causes of the disease

Colorectal tumors are precancerous lesions, which are characterized by large and small protrusions on the mucosa of the large intestine.

(two) pathogenesis

Colorectal adenomas are characterized by large and small protrusions on the large intestine mucosa, which can be divided into pedicle type and broad-based type. How many velvety components can be seen on histological sections, according to the proportion of villous components in adenomas. Different adenomas are divided into tubular adenomas (20% or less of villous components), mixed adenomas (20% to 80% of villous components) and villous adenomas (more than 80% of villous components) Clinically, tubular adenomas are the most common, accounting for about 70%. Due to their classification characteristics, the histological type of adenomas can only be determined after pathological examination of intact adenomas.

Although most of the colorectal cancers have evolved from colorectal adenomas, not all colorectal adenomas have cancerous changes. The canceration of adenomas is related to the following factors.

1. Adenoma size: Generally speaking, with the increase of adenoma, the chance of canceration increases significantly. According to reports in the literature, the incidence of carcinoma in situ of adenoma <1cm, 1-2cm, and >2cm is 1.7%. 2.6%, 6, 5% to 24.3%, 12% to 25%, the incidence of invasive cancer is 1% to 1.3%, 9.5% to 9.8%, 41.7% to 46.1%, and a flat ridge has been found in recent years. Small adenomas, often <1cm in diameter, may be associated with a central depression. The malignant rate is high, but it is easy to miss diagnosis, so careful examination should be taken during colonoscopy.

2. Pathological type: The more villous components in adenoma, the more easily cancerous, the villous adenoma has the highest cancer rate, the mixed adenoma is second, and the tubular adenoma has a lower cancer rate.

3. Adenoma shape: The cancer rate of broad-based adenoma is significantly higher than that of pedicle-type adenoma.

4. The degree of atypical hyperplasia of adenoma: With the increase of atypical hyperplasia, the canceration rate increased significantly. The incidence of carcinogenesis in mild dysplasia was about 5.7%, moderate was 18%, and severity was 34.5%.

Colorectal adenoma prevention

Pay attention to rest, work and rest, life in an orderly manner, and maintaining an optimistic, positive and upward attitude towards life can be of great help in preventing diseases.

Colorectal adenoma complications Complications, intussusception, intestinal obstruction

1. Blood in the stool: It can be blood in the stool of different degrees.

2. Intussusception or intestinal obstruction: Large pedicled adenoma can cause intussusception or intestinal obstruction.

Colorectal adenoma symptoms common symptoms bloody diarrhea, large intestine, black intestine, intussusception, colonic obstruction, abdominal pain

The symptoms of colorectal adenoma are related to their size and location. Small adenomas are often asymptomatic. The symptoms of larger adenomas can be summarized as follows:

1. Blood in the stool: It can be a different degree of blood in the stool. If the amount of bleeding is small or the adenoma is located in the right colon, it is often difficult to detect the naked eye. The fecal occult blood test may be positive.

2. Intestinal irritation: manifested as increased diarrhea or frequent bowel movements, more common in villous adenomas.

3. Intussusception or intestinal obstruction: Large pedicled adenoma can cause intussusception or intestinal obstruction and cause abdominal pain.

Examination of colorectal adenoma

1. Biopsy: multiple or multiple materials should be taken. It is best to remove all polyps for examination to improve the positive rate of diagnosis.

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

3. Rectal examination: It is the most simple and reliable method to check the rectum within 7~8cm from the anus. Touching the induration is a reliable indicator of adenoma carcinogenesis.

4. X-ray examination: X-ray examination of barium enema is not easy to detect small adenomas, and it is not easy to show low-grade, especially rectal adenomas. Double contrast gas angiography can improve the detection rate of adenomas.

5. Endoscopy: including colonoscopy, sigmoidoscopy, fiberoptic colonoscopy, etc., is currently the most reliable method of examination, but there is still the possibility of missed diagnosis, polyps found in endoscopy should be biopsy, adenoma cancer endoscopy The following are often manifested as: adenoma enlargement, surface erosion, ulceration, necrotic appearance, broad-based or short pedicle, basal stiffness of the adenoma, ablation of adenoma tissue, etc., reportedly enlarged endoscopic binding staining The method can determine whether the tumor has cancerous or invasive depth, and the use of immunoendoscopy can accurately distinguish between good and malignant lesions.

Diagnosis and diagnosis of colorectal adenoma

Diagnostic criteria

1. Clinical manifestations.

2. Laboratory and other auxiliary inspections.

Differential diagnosis

1. Intestinal tuberculosis: Most patients have primary tuberculosis lesions, such as afternoon fever, night sweats, weight loss and other symptoms of tuberculosis poisoning, stools are mostly yellow loose stools, with mucus and less pus, diarrhea and constipation often appear alternately, 0T Positive test, colonoscopy and X-ray examination are helpful for diagnosis.

2. Colon polyps: There may also be blood in the stool, changes in bowel habits, abdominal pain and other symptoms, easily confused with colon cancer, but colonoscopy and biopsy can be identified.

3. appendix abscess: history of acute or chronic appendicitis or right lower quadrant pain, may have tenderness in the lower right abdomen and abdominal muscle tension, peripheral blood picture is elevated, abdominal B-ultrasound or CT examination can be found in the lower abdomen fluid mass, colonoscopy or sputum X-ray examination of the enema can rule out cecal tumors.

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