Colon tumors can be benign or malignant. Tubular adenoma of the colon and carcinoid of the appendix (worm-shaped appendix) are benign neoplasms. Colon adenocarcinoma is a malignant neoplasm that develops from glandular epithelial cells. This is one of the histological types of colon cancer.
At the Yusupov Hospital, the presence of colon tumors is determined using modern diagnostic methods. Histologists verify the type of tumor by examining tissue samples obtained during a biopsy under a microscope. In the presence of tubular adenoma of the colon, a description of the microslide is carried out.
Depending on the location and histological type of the tumor, the patient’s condition and the presence of concomitant diseases, oncologists develop an individual treatment plan for the patient. Severe cases of colon carcinoma are discussed at an expert council meeting. Candidates and doctors of medical sciences, doctors of the highest category take part in its work. Leading oncologists in Moscow make a collegial decision on patient management tactics.
Adenocarcinoma can develop from tubular-villous adenoma of the colon with dysplasia. The sequence “adenoma - cancer” has been confirmed by numerous scientific studies. The risk of developing malignant neoplasms of the rectum and colon in individuals with adenomatous polyps is 3–5 times higher than in the general population. Due to the high risk of malignant transformation of tubular adenoma of the colon with dysplasia, oncologists at the Yusupov Hospital carry out early diagnosis and take preventive measures to reduce the incidence of colon adenocarcinoma.
Histological types of colon adenomas
There are 3 histological types of colon adenomas:
- Tubular;
- Tubular villous;
- Villous.
The separation criterion is the ratio of villous and tubular structures. Tubular adenoma of the colon - what is it? Microscopically, tubular adenoma is represented by proliferating adenomatous epithelium. The tumor consists of branching and significantly convoluted glandular tubes, longer than in the normal intestinal mucosa. In tubular adenoma, no more than 25% villous tissue is present. Tubular adenoma of the colon has a mucous membrane-covered base. It is represented by connective tissue, smooth muscle cells and blood vessels. Tubular adenomas have a stalk and a smooth lobulated surface. Less often they are located on a wide base. Creeping tubular adenomas, which protrude slightly above the surface of the mucous membrane, are very rare.
In tubular-villous adenomas, the number of villi increases, which can be detected both on the surface of the polyp and inside large glands. The glands lengthen, acquire an irregular shape, and fit tightly to each other. The degree of epithelial dysplasia increases. In tubular-villous adenoma, the percentage of villous tissue varies from 25 to 75%. The tumor consists of pronounced lobules and has small areas with villi or very small lobules.
Villous adenoma consists of thin finger-like outgrowths of the connective tissue of the lamina propria, which are covered with epithelium. In villous adenomas, a small number of glands and 75% of the villous component can be found. Macroscopically, villous adenomas have a wide base and a “shaggy” surface. There is a special histological type of colon adenoma - serrated adenoma. The tumor is close in structure to a hyperplastic polyp, but has the potential for malignancy.
Adenomatous epithelium belongs to the category of neoplastic. For this reason, each adenoma has signs of dysplasia of varying severity. Histologists distinguish 3 degrees of dysplasia of tubular adenoma of the colon:
- 1st degree – weak;
- 2 degrees – moderate;
- Grade 3 – severe.
Tubular adenoma of the colon with low grade dysplasia is a poorly differentiated tumor. It can transform into adenocarcinoma.
Description
An adenoma affecting the large intestine is a benign growth. This disease is also called a polyp. Education has a broad base from which it grows.
The formation of adenoma is carried out due to glandular cells present in the intestinal cavity in large numbers.
Taking into account the fact that the tumor has a base, in medicine it is also called tubular-papillary adenoma.
The structure of the neoplasm resembles a branching tree surrounded by connective tissue. The peculiarity of the tumor is its slow growth.
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- May 27, 2020
May have clear or unclear boundaries. Taking into account the fact that the structure of the neoplasm is branched, the pathology has another name - tubular-villous adenoma.
The disease is most often diagnosed in older people. According to statistics, such colon adenoma accounts for about 15 percent of all diseases of the organ.
Classification of colon adenocarcinomas
Histologists distinguish the following types of malignant neoplasms of the large intestine:
- Well-differentiated colon adenocarcinoma;
- Moderately differentiated colon adenocarcinoma g2;
- Poorly differentiated adenoma.
Glandular cancer can generally be represented by the following types of colon carcinomas: tubular, mucinous, signet ring cell, squamous cell. Tubular adenocarcinomas consist of tubular structures. Tumors of this type occur in more than 50% of patients with glandular cancer. They have blurred contours and small sizes.
Mucinous adenocarcinoma consists of mucous components and epithelial structures and has no defined boundaries. Metastasis occurs through the lymphogenous route. The high risk of recurrence is due to insensitivity to radiotherapy.
Signet ring cell adenocarcinomas are characterized by a highly aggressive clinical course. Most patients with tumors of this type, who seek medical help at the Yusupov Hospital for the first time, already have metastases in the lymph nodes and liver. Oncological disease is most often observed in young patients.
Squamous cell adenocarcinomas form in the area of the anal canal. The tumor consists of flat epithelial cells. The clinical course of squamous cell adenocarcinomas is characterized by a high level of malignancy. They often recur, growing into the tissue of the vagina, ureters, bladder, and prostate gland. The five-year survival rate for squamous cell adenocarcinomas does not exceed 30%.
Treatment of the disease
Treatment of tubular neoplasm can only be surgical. The operation is performed in one of two ways. Most polyps are removed using electrocoagulation. This procedure is less traumatic than others and is characterized by a short rehabilitation period. Electrocoagulation is not used to remove polyps located in the anus. Otherwise, complications may arise.
Treatment of tubular adenoma of the sigmoid colon can also be carried out by complete excision of the tumor . In this case, part of the intestine is removed along with the tumor. This operation is performed only for cancerous tumors. Large polyps are destroyed in parts.
It is impossible to predict the appearance of tubular polyps. The reasons why adenomas form on the mucous membranes of the gastrointestinal tract have not yet been clarified. Perhaps poor nutrition plays a big role. If blood clots appear in the stool or other symptoms, you should immediately contact your physician, who will refer you for examination. There is no need to be afraid of a benign neoplasm, but if the polyps have a different shape, then to save your own life you need to be under the supervision of a doctor.
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Causes of adenomas and adenocarcinomas of the colon
The development of tubular adenoma of the colon is promoted by nutritional factors: high fat content and low dietary fiber. Changes in diet affect the likelihood of developing adenoma and adenocarcinoma. Refined fats can disrupt the proliferation of epithelial cells. Nutrient components found in fruits, vegetables and other foods can regulate colon carcinogenesis and influence the progression of adenoma to carcinoma.
The individual risk of developing colon adenoma increases in first-degree relatives of patients with colorectal cancer. The likelihood of developing colorectal carcinomas increases if a person has first-degree relatives diagnosed with colon cancer before the age of 50 years. The risk is especially great if these relatives are brothers or sisters. Environmental factors can interact with the genetic factors of the body, leading to the emergence or progression of “adenoma-carcinoma”.
An increase in the size of the polyp, the number of villi and severe dysplasia increase the risk of malignancy of colon adenoma. According to statistics, 4.8% of tubular, 22.5% of tubular villous and 40.7% of villous adenomas are converted into adenocarcinoma. The risk of transformation of benign neoplasms into malignant tumors increases with the degree of dysplasia. 5.7% of adenomas with mild dysplasia, 18% with moderate dysplasia and 34.5% with severe dysplasia transform into adenocarcinoma of the colon.
Villous, tubulovillous adenomas, and adenomas larger than 1 cm increase the risk of subsequent development of colon adenocarcinoma. This risk is higher in patients with multiple polyps.
Degrees
The process goes through three stages of development
First
Tubular adenoma of the colon with grade 1 dysplasia is characterized by slight thickening of the epithelial layers. The basal layer also splits.
As a result of the fact that the cells are in mitotic activity, the development of the inflammatory process begins. Microscopic examination reveals an increase in the ratio between the nucleus and cytoplasm. Nuclear hypochromia is also determined.
Second
A distinctive feature of adenoma with moderate dysplasia is polymorphism, when cellular structures become of different sizes and shapes, and proliferation. The basal layer has unclear outlines.
Third
The degree with focal severe epithelial dysplasia is characterized by changes in the nuclei to hyperchromic. Cells change even more in size and shape.
Changed cellular structures occupy more than half of the entire epithelial layer.
Tags: adenoma, dysplasia, intestine, colon, tubular, moderate
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Symptoms and diagnosis of colon adenomas
Most colon adenomas do not manifest themselves clinically. They are discovered incidentally during screening tests or examinations for complaints that are not related to them. Sometimes adenomas cause significant bleeding or lead to chronic anemia due to prolonged hidden blood loss. Large rectal adenomas may be accompanied by tenesmus and mucus secretion. The production of mucus in large quantities causes electrolyte imbalance. Distal rectal adenomas may prolapse through the anus.
Doctors at the Yusupov Hospital identify colon adenomas using sigmoidoscopy and colonoscopy. Adenoma of the large intestine most often takes the form of a polyp located on a broad base or connected to the intestinal wall with a pedicle. Its stalk length depends on the growth rate of the polyp localization. Rapidly growing adenomas have a wide base. Slowly growing ones are located on a stalk, which is formed as a result of peristalsis and stretching of the polyp by a peristaltic wave.
Some colon adenomas have a deepened or flat appearance. They do not rise above the surface of the mucous membrane. They can be visually identified by changes in color, structure of the mucous membrane, and the absence of a capillary network. The Yusupov Hospital uses a simple and effective method for their identification - chromoscopy with indigo carmine.
Clinical manifestations
Symptoms depend on the stage of development of the pathology, among which are:
- epithelial dysplasia – there are no significant changes in the structure and process of cell division;
- second degree of dysplasia - some changes occur in the tissues, anomalies appear in their structure. The rate of cell division increases;
- interepithelial neoplasia - the process becomes difficult to reverse, the neoplasm is already characterized as malignant.
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It is often possible to detect the disease in the first stage by chance; noticeable symptoms appear in the second stage, when the tumor size reaches 20 mm. The main symptom is acute pain that occurs during bowel movements and goes away after a certain period of time. You may also experience:
- disruptions in the digestion process and accompanying stomach pain, bloating, flatulence;
- stool disorders - constipation and/or diarrhea;
- the appearance of blood (black stool) or mucus in the feces;
- itching, discomfort, sensation of the presence of a foreign body in the intestines;
- bleeding from the anus and accompanying iron deficiency anemia.
The most dangerous complication of adenomatous polyps is malignant tissue degeneration, however, even in its absence, disturbances in the body’s water-electrolyte balance and intestinal obstruction may occur.
Tactics for managing patients with colorectal adenomas
When, during sigmoidoscopy, proctologists at the Yusupov Hospital discover a small polyp, the size of which does not exceed 1 cm, they perform a biopsy. If an adenoma is morphologically verified, colonoscopy is performed to identify possible synchronous lesions in the proximal colon. In this case, the distal adenoma, identified earlier, is removed. Colonoscopy is performed even when sigmoidoscopy reveals a small tubular adenoma of the colon.
If during sigmoidoscopy doctors detect a polyp measuring 1 cm or more, there is no need to perform a biopsy. The tumor is removed during a colonoscopy, which is performed to identify synchronous tumor lesions in the upper parts of the colon. If a non-tumor polyp (hyperplastic, inflammatory) is detected, there is no need for further observation.
After a total colonoscopy and removal of all polyps, a subsequent colonoscopy is performed after 3 years. In case of incomplete removal of the polyp, removal of large broad-based adenomas, multiple polyps, subsequent colonoscopies are performed at an earlier date. If no new adenomas are detected during a control colonoscopy, the observation interval is increased to five years.
In the presence of large wide-based polyps, the risk of complications during endoscopic removal of which is high, surgical intervention is performed using a laparotomic approach. After complete endoscopic removal of adenomatous polyps with severe dysplasia), there is no need for additional examination or treatment of patients. Follow-up colonoscopy is performed within three years. If no new adenomas are detected, the observation interval is increased to 5 years.
After endoscopic removal of an adenomatous polyp with signs of a malignant tumor, further tactics are determined based on prognostic criteria. If the endoscopist is convinced that the polyp was completely removed, a morphological examination revealed a well-differentiated or moderately differentiated adenocarcinoma, there was no invasion of the blood or lymphatic vessels, and no malignant cells were found at the resection margins, endoscopic polypectomy is considered radical. When there is no confidence in the complete removal of the adenoma, a morphological examination reveals low-grade adenocarcinoma, there is invasion of the lymphatic or blood vessels, malignant cells are found at the resection margins, the patient undergoes surgical intervention due to the high risk of residual adenocarcinoma and metastases to regional lymph nodes.
If there are signs of intestinal discomfort, the cause of which may be tubular or tubular villous adenoma of the colon, well-differentiated or poorly differentiated adenocarcinoma, carcinoid of the appendix, contact the oncologists of the clinic. You will be given an appointment with a doctor at the Yusupov Hospital. You will receive advice from leading proctologists and oncologists at a time convenient for you. Timely treatment of colon adenoma prevents the development of adenocarcinoma.
Author
Natalya Aleksandrovna Vyaznikova
Oncologist
Symptoms of the disease
With tubular adenoma of the sigmoid colon in the initial stage, the disease is asymptomatic. As soon as the polyp increases in size to 1 centimeter, bleeding appears. It is found on the surface of the stool. Blood streaks are light or scarlet in color. At the same time, the intestines continue to work as usual, the neoplasm does not provoke concomitant diseases.
When polyps grow, a person may experience constipation, discomfort in the anus, and bloating . Pain occurs during bowel movements. Sometimes the disease is accompanied by diarrhea. Symptoms can appear individually or all together.
Bibliography
- ICD-10 (International Classification of Diseases)
- Yusupov Hospital
- Cherenkov V. G. Clinical oncology. — 3rd ed. - M.: Medical book, 2010. - 434 p. — ISBN 978-5-91894-002-0.
- Shirokorad V.I., Makhson A.N., Yadykov O.A. The state of oncourological care in Moscow // Oncourology. - 2013. - No. 4. - P. 10-13.
- Volosyanko M.I. Traditional and natural methods of preventing and treating cancer, Aquarium, 1994
- John Niederhuber, James Armitage, James Doroshow, Michael Kastan, Joel Tepper Abeloff's Clinical Oncology - 5th Edition, eMEDICAL BOOKS, 2013
Complications
One of the more serious consequences is the degeneration of an adenoma into a cancerous tumor. In addition, the process may be complicated by hidden bleeding, the development of acute intestinal obstruction, intoxication of the body, or intestinal atresia (lack of peristalsis and inability to move feces).
In most cases, the diagnosis of the disease occurs in the later stages, when degeneration into a malignant process has already occurred. This is explained by the fact that for a long time the pathology does not manifest itself in any way. Detection of the disease in the early stages is only possible with a colonoscopy.
Among other possible complications, experts identify the following:
- hidden bleeding as a result of trauma to intestinal vessels;
- artesia of the intestinal canal - lack of peristalsis, which leads to stagnant fecal processes;
- intoxication of the body;
- acute intestinal obstruction.
If you experience abdominal pain and discomfort in the anus, you need to consult a specialist.
