Carcinoids- the most common tumors are from neuroendocrine cells (cells of the APUD system). These cells are derivatives of the neural crest. They are widely distributed in the body and contain and secrete some biologically active peptides. Most often carcinoids develop in gastrointestinal tract(85%), especially in the small intestine, but also in the lungs (10%), less commonly affecting other organs (for example, the ovaries). Intestinal carcinoids rarely (in 10% of cases) manifest clinically. This is explained by the rapid destruction of biologically active peptides in the liver. Only with metastases of intestinal carcinoid to the liver do symptoms appear in 40-45% of patients. As for ovarian carcinoids and bronchial carcinoids, they are capable of causing a characteristic syndrome in the early stages of the disease.

Carcinoid syndrome- a combination of symptoms that arise due to the release of hormones by tumors and their entry into the bloodstream.

Pathogenesis (what happens?) during Carcinoid syndrome:

Carcinoid tumors can appear where there are enterochromaffin cells, basically throughout the body. More carcinoid tumors (65%) develop in the gastrointestinal tract. In most cases, carcinoid tumors develop in the small intestine, appendix, and rectum. Carcinoid tumors develop most rarely in the stomach and colon; pancreas, gallbladder and the liver are least susceptible to the development of a carcinoid tumor (despite the fact that carcinoid tumors usually metastasize to the liver).

Approximately 25% of carcinoid tumors affect the airways and lungs. The remaining 10% can be found anywhere. In some cases, doctors cannot locate the carcinoid tumor despite symptoms of carcinoid syndrome.

Carcinoid tumor small intestine

In general, tumors of the small intestine (benign or malignant) are rare, much less common than tumors of the colon or stomach. Small carcinoid tumors of the small intestine may not cause any symptoms other than mild abdominal pain. For this reason, it is difficult to determine the presence of small bowel carcinoid tumor on early stage, at least until the patient is operated on. It is possible to detect only a small proportion of small intestinal carcinoid tumors in the early stages, and even then this occurs unexpectedly on x-ray. Typically, carcinoid tumors of the small intestine are diagnosed late stages, when the symptoms of the disease make themselves felt and usually after metastases have appeared.

Approximately 10% of carcinoid tumors of the small intestine cause carcinoid syndrome. Typically, the development of carcinoid syndrome means that the tumor is malignant and has reached the liver.

Carcinoid tumors often obstruct the small intestine when they become large. Symptoms of small intestinal obstruction include paroxysmal abdominal pain, nausea and vomiting, and sometimes diarrhea. Obstruction can be caused by two various mechanisms. The first mechanism is tumor enlargement within the small intestine. The second mechanism is twisting of the small intestine due to fibrosing mesenteritis, a condition caused by a tumor in which extensive scarring occurs in the tissues located in close proximity to the small intestine. Fibrosing mesenteritis sometimes obstructs the arteries that carry blood to the intestines, which can result in the death of part of the intestine (necrosis). In this case, the intestines can rupture, which is a serious threat to life.

Appendiceal carcinoid tumor

Although tumors in the appendix are quite rare, carcinoid tumors are the most common tumors in the appendix (about half of all appendiceal tumors). In fact, carcinoid tumors are found in 0.3% of removed appendixes, but most of them do not grow larger than 1 cm and do not cause any symptoms. In most cases, they are found in appendices that have been removed for reasons other than tumors. Representatives of many institutions believe that appendectomy is the most suitable treatment such small appendiceal carcinoid tumors. The chances of the tumor returning after an appendectomy are very low. Appendiceal carcinoid tumors larger than 2 cm in 30% can be malignant and form local metastases. Thus, carcinoid tumors larger size should be deleted. A simple appendectomy will not help in this case. Fortunately, carcinoid tumors large size are quite rare. Carcinoid tumors in the appendix, even with metastases to local tissues, usually do not cause carcinoid syndrome.

Rectal carcinoid tumors

Rectal carcinoid tumors are often diagnosed incidentally during plastic sigmoidoscopy or colonoscopy. Carcinoid syndrome is rare in rectal carcinoid tumors. The likelihood of metastases is related to tumor size; 60-80% chance of metastases for tumors larger than 2 cm. For carcinoid tumors smaller than 1 cm, 2% chance of metastases. In summary, small rectal carcinoid tumors are usually successfully removed, but larger tumors (greater than 2 cm) require extensive surgery, which can even result in partial removal of the rectum in some cases.

Gastric (stomach) carcinoid tumors

There are 3 types of gastric (stomach) carcinoid tumors: type I, type II and type III.

Type 1 gastric carcinoid tumors are usually less than 1 cm in size and are benign. There are complex tumors that spread throughout the stomach. They usually appear in patients with pernicious anemia or chronic atrophic gastritis (a condition in which the stomach stops producing acid). The lack of acid causes the cells in the stomach, which produce the hormone gastrin, to release large amounts of gastrin, which enters the blood. (Gastrin is a hormone secreted by the body to enhance the activity of stomach acid. The acid in the stomach blocks the reproduction of gastrin. When pernicious anemia or chronic atrophic gastritis, the lack of acid is the result of an increase in the amount of gastrin). In addition, gastrin also influences the transformation of enterochromaffin cells in the stomach into a malignant carcinoid tumor. Treatment for type 1 carcinoid tumors includes treatments such as somatostatin-containing drugs that stop the production of gastrin or surgical removal the part of the stomach that produces gastrin.

The second type of gastric carcinoid tumor is less common. Such tumors grow very slowly and the likelihood of them becoming malignant is very low. They appear in patients with a rare genetic disorder like MEN (multiple endocrine neoplasia) type I. In such patients, tumors arise in other endocrine glands, such as the pineal gland, parathyroid gland and pancreas.

The third type of gastric carcinoid tumor are tumors larger than 3 cm that are isolated (appearing one or more at a time) in a healthy stomach. Tumors of the third type are usually malignant and there is a high probability of their deep penetration into the walls of the stomach and the formation of metastases. Type 3 tumors can cause abdominal pain and bleeding, as well as symptoms due to carcinoid syndrome. Type 3 gastric carcinoid tumors usually require surgery to remove the stomach and nearby lymph nodes.

Carcinoid tumors of the colon

Colon carcinoid tumors usually form on the right side of the colon. Like carcinoid tumors of the small intestine, carcinoid tumors of the colon are often discovered at advanced stages. Thus, medium size the tumor at diagnosis is 5 cm, and metastases are present in 2/3 of patients. Carcinoid syndrome is rare in carcinoid tumors of the colon.

Symptoms of Carcinoid Syndrome:

Symptoms of carcinoid syndrome vary depending on what hormones the tumors secrete. Typically these are hormones such as serotonin, bradykinin (promotes pain), histamine and chromogranin A.

Typical manifestations of carcinoid syndrome:

• Hyperemia (redness)
• Diarrhea
• Abdominal pain
• Wheezing due to bronchospasm (narrowing respiratory tract)
• Heart valve damage
• Surgery can cause a complication known as carcinoid crisis.

Hyperemia

Flushing is the most common symptom of carcinoid syndrome. In 90% of patients, hyperemia occurs during the disease. Flushing is characterized by redness or discoloration of the face and neck (or upper parts body), as well as an increase in temperature. Attacks of hyperemia usually occur suddenly, spontaneously, they can be caused by emotional, physical stress or alcohol consumption. Attacks of hyperemia can last from a minute to several hours. Congestion may be accompanied by a rapid heart rate, low blood pressure, or dizziness if blood pressure drops too much and blood is not getting to the brain. Rarely, hyperemia is accompanied by high blood pressure. The hormones that are responsible for hyperemia are not fully recognized; These may include serotonin, bradykinin and substance P.

Diarrhea

Diarrhea - second important symptom carcinoid syndrome. About 75% of patients with carcinoid syndrome experience diarrhea. Diarrhea often occurs along with flushing, but can also occur without it. In carcinoid syndrome, diarrhea is most often caused by serotonin. Medicines drugs that block the action of serotonin, such as ondansetron (Zofran), often relieve diarrhea. Sometimes diarrhea in carcinoid syndrome can occur due to local exposure to a tumor that obstructs the passage of the small intestine.

Heart diseases

Heart disease occurs in 50% of patients with carcinoid syndrome. Carcinoid syndrome usually leads to fibrotic changes pulmonary valve of the heart. Impaired valve movement reduces the heart's ability to pump blood from the right ventricle to the lungs and other parts of the body, which can lead to heart failure. Typical symptoms heart failure include: liver enlargement, leg swelling, fluid accumulation in abdominal cavity(ascites). The cause of damage to the tricuspid and pulmonary valves of the heart in carcinoid syndrome, in most cases, is intense long-term exposure serotonin.

Carcinoid crisis

Carcinoid crisis is a dangerous condition that can occur during surgery. A crisis is characterized by a sudden fall blood pressure, which causes the development of shock. This condition may be accompanied by an excessively rapid heartbeat, increased content glucose in the blood, as well as severe bronchospasm. Carcinoid crisis can lead to fatal outcome. The most the best way Prevention of a carcinoid attack is surgery using somatostatin before surgery.

Wheezing

Wheezing occurs in approximately 10% of patients with carcinoid syndrome. Wheezing is a consequence of bronchospasm (spasm of the airways), which occurs as a result of the release of hormones by a carcinoid tumor.

Abdominal pain

Abdominal pain is a common symptom in patients with carcinoid syndrome. Pain may occur due to metastases in the liver, due to the tumor affecting neighboring tissues and organs, or due to intestinal obstruction(read about small intestinal carcinoid tumor below).

Diagnosis of Carcinoid Syndrome:

Diagnosis of carcinoid syndrome confirmed by an increase in the daily urine level of the serotonin metabolite - 5-hydroxyindoleacetic acid.

Treatment of Carcinoid Syndrome:

Treatment of carcinoid syndrome: radical surgical removal of the tumor. For metastases that cannot be removed, therapy with octreotide is prescribed - long-term active analogue somatostatin.

For frequent attacks, methyldopa preparations are used (dopegit 0.25-0.5 g 3-4 times a day), opium preparations for diarrhea. It is possible to use prednisolone in a dose of up to 20-30 mg per day.

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Other diseases from the group Oncological diseases:

– a complex of symptoms that arise as a result of the hormonal activity of tumors from cells of the APUD system. Includes hot flashes, persistent diarrhea, fibrotic lesions right half heart disease, abdominal pain and bronchospasm. During surgical interventions, a life-threatening carcinoid crisis may develop. Carcinoid syndrome is diagnosed on the basis of anamnesis, complaints, objective examination data, results of determining the level of blood hormones, CT, MRI, scintigraphy, radiography, endoscopy and other studies. Treatment is surgical removal of the tumor, drug therapy.

ICD-10

E34.0

General information

Carcinoid syndrome is a symptom complex observed in potentially malignant, slow-growing neuroendocrine tumors that can occur in almost any organ. In 39% of cases, neoplasms that provoke carcinoid syndrome are localized in small intestine, in 26% - in the appendix, in 15% - in the rectum, in 1-5% - in other parts of the large intestine, in 2-4% - in the stomach, in 2-3% - in the pancreas, in 1% - in the liver and 10% - in the bronchi. In 20% of cases, carcinoid tumors of the gastrointestinal tract are combined with other neoplasms of the large intestine. Carcinoid syndrome usually develops between the ages of 50 and 60, and men and women are equally affected.

For carcinoid syndrome caused by a tumor in the appendix, an appendectomy is performed. Some oncologists additionally remove nearby lymph nodes. Palliative surgical interventions are indicated at the stage of metastasis and involve the removal of large lesions (both secondary and primary) to reduce hormone levels and reduce the severity of carcinoid syndrome. Another way to reduce the manifestations of carcinoid syndrome is embolization or ligation of the hepatic artery.

Medical statistics show that the number oncological diseases is growing steadily. Fatal outcomes are being recorded more and more frequently every year. This fact is causing increasing concern and is forcing doctors to preventive work among the population in order to at least slightly restrain such aggressive

Carcinoid syndrome: what is it?

Carcinoids are the most common cell tumors. These cells can be found in any organ and tissue of the body. Their main function is the production of highly active protein substances. About eighty percent of all carcinoids are located in the gastrointestinal tract, with the lungs coming in second. Much less often, in only five percent of cases, neoplasms are found in other organs and tissues.

Carcinoid syndrome and carcinoid tumor are inseparable from each other, since the syndrome is a set of symptoms that appear against the background of growth and activity malignant formation. After all, the body reacts to hormones secreted by the tumor entering the blood. Intestinal carcinoids can be “silent”, that is, they do not manifest themselves in any way until metastases appear and the disease reaches the terminal stage.

Reasons

Researchers do not yet have enough information to understand why carcinoid syndrome and carcinoid tumor develop. Scientists can make hypotheses regarding the etiology of the disease, but everyone agrees that immune system at some point, it ceases to recognize the mutated cells of the APUD system (an acronym from the first letters of the words “amines”, “precursor”, “assimilation”, “decarboxylation”).

One malignant cell is enough for it to develop into a full-fledged neoplasm, which will produce hormones and change all biochemical processes in the human body to suit its own needs.

Pathogenesis

How does carcinoid syndrome develop? What is this and how to prevent it? Considering that neuroendocrine cells are located throughout the body, and clinical manifestations The tumor practically does not heal; doctors are unable to stop this process.

At one point, a “breakdown” of DNA occurs in the cell, which is incorrectly restored or continues to function with the damaged fragment. This leads to dysfunction of the cell and its uncontrolled division. If the body is healthy, the immune system will react to the mutation and get rid of the suspicious element. If this does not happen, the cell will multiply, create millions of copies of itself and begin to spread throughout the body toxic substances and hormones.

Often doctors are unable to identify the location of the tumor, despite clinically evident carcinoid syndrome.

Lung carcinoma

Only in ten percent of cases in respiratory system a tumor and, accordingly, carcinoid syndrome may develop. Signs in the lung will be nonspecific, and sometimes there will be none at all. This is due to the relatively small size of the tumor and the absence of metastasis. Patients seek help already advanced disease and, as a rule, not to an oncologist, but first to a therapist. It can treat bronchiolitis, asthma or respiratory failure until the presence of an oncological process is suspected.

The symptoms in this case are atypical:

• rapid, strong heartbeat;
• dyspeptic symptoms;
• feeling of heat and rush of blood to the upper half of the body;
• cough, shortness of breath;
• bronchospasm.

With such a set of disorders, it is difficult to suspect carcinoid. No exhaustion, sudden weight loss, decreased immunity, fatigue, etc. characteristic symptoms oncological process.

Small bowel tumor

In the small intestine, a tumor and the accompanying carcinoid syndrome are recorded a little more often than in the lungs. Its signs are very scarce. Often only nonspecific abdominal pain is present. This is due to the small size of the tumor. Sometimes it cannot be detected even during surgery. Often the formation is noticed accidentally during an X-ray examination.

Only about ten percent of all small intestinal tumors of this etiology are the cause of carcinoid syndrome. For the doctor, this means that the process has become malignant and has spread to the liver. Such tumors can cause obstruction of the intestinal lumen and, as a result, intestinal obstruction. The patient is admitted to the hospital with cramping pain, nausea, vomiting and stool disorders. And the cause of this condition will only be found out on the operating table.

Obstruction can be caused either directly by the size of the tumor or by torsion of the intestine due to fibrosis and inflammation of its mucous membrane. Sometimes scars disrupt the blood supply to an area of ​​the intestine, which leads to necrosis and peritonitis. Any of these conditions is life-threatening and can lead to the death of the patient.

Appendix tumor

Tumors of the appendix - rare occurrence by itself. Among them, carcinoids occupy an honorable first place, but practically do not cause carcinoid syndrome. Their signs are extremely scarce. As a rule, these are findings of pathologists after appendectomies. The tumor does not even reach one centimeter in size and behaves very “quietly”. The chances that after removal of the appendix the tumor will appear in some other place are negligible.

But if the detected tumor was two centimeters or more in size, then one should be wary of metastasis to local lymph nodes and dissemination of tumor cells to other organs. In this case, a regular appendectomy will not cope with all the screenings, and oncologists will have to be involved to carry out complex treatment.

Rectal carcinoid tumor

Another localization in which carcinoid syndrome is practically not expressed. There are no signs and tumors are accidentally found during diagnostic procedures such as colonoscopy or sigmoidoscopy.

The likelihood of malignancy (malignancy) and the appearance of distant metastases depends on the size of the tumor. If its diameter exceeds two centimeters, then the risk of complications is about eighty percent. If the neoplasm does not reach even one centimeter in diameter, then you can be ninety-eight percent sure that there are no metastases.

Therefore, the treatment approach in these two cases will be different. A small tumor is usually removed sparingly, but if there are signs of malignancy, then removal of the entire rectum, as well as chemotherapy, will be required.

Gastric carcinoid

There are three types of gastric carcinoid tumors that cause carcinoid syndrome. Signs of type 1 tumors:

• small sizes (up to 1 cm);
• benign course.

Complex spread of the tumor is possible when the process involves the entire stomach. They are associated with pernicious anemia or chronic gastritis at the patient. Treatment of such tumors consists of taking somatostatins, inhibiting gastrin production, or gastric resection.

Tumors of the second type grow slowly and rarely become malignant. They prevail in patients with such genetic disorder as multiple endocrine neoplasia. Not only the stomach, but also the pineal gland, thyroid gland, and pancreas can be affected.

The third type of tumors are large tumors growing in a healthy stomach. They are malignant, penetrate deeply into the wall of the organ and give multiple metastases. May cause perforation and bleeding.

Colon tumors

The colon is where carcinoid syndrome and carcinoid tumor are most often diagnosed. A photo of the mucous membrane during examination of this segment of the intestine shows the presence of large (five centimeters or more) tumors. They metastasize and are almost always malignant.

In such cases, oncologists advise radical surgery with adjuvant and neoadjuvant chemotherapy to achieve better effect. But the survival prognosis for these patients is still unfavorable.

Carcinoid syndrome: symptoms, photos

The manifestations of carcinoid syndrome depend on what substances the tumor secretes. These may be serotonin, bradykinin, histamine or chromogranin A. The most typical signs diseases are:

• Redness of the skin of the face and upper half of the body. Occurs in almost all patients. Accompanied by a local increase in temperature. Seizures occur spontaneously and may be triggered by alcohol, stress, or physical activity. In this case, tachycardia is observed and blood pressure drops.
• Stool disorder. Present in ¾ of patients. As a rule, this occurs due to irritation of the mucous membrane digestive tract, intestinal obstruction.
• Cardiac dysfunction occurs in half of the patients. Carcinoid syndrome contributes to the formation of stenoses of the heart valves and causes heart failure.
• Wheezing in the lungs is a consequence of bronchospasm.
• Abdominal pain is associated with the appearance of metastases in the liver, intestinal obstruction, or tumor growth into other organs.

Carcinoid crisis is a condition characterized by sharp drop pressure during surgery. Therefore, patients are prescribed somatostatin before such manipulations.

Diagnostics

Is it possible to detect carcinoid syndrome? Signs, photos, treatment of scattered symptoms does not give any clear clinical picture, no visible results. Most often, the tumor is an accidental discovery by a surgeon or radiologist. In order to confirm the presence of a neoplasm, you need to do a biopsy of the affected area and examine the tissue.

You can also use detection tests higher level hormones, but these data may indicate several diseases, and the doctor has yet to figure out which one he is dealing with. The most specific test is the amount of 5-hydroxyindoleacetic acid. If its level is elevated, then the probability of carcinoid is almost 90%.

Chemotherapy

Does it make sense to treat carcinoid syndrome with chemotherapy? Signs, photo of the mucous membrane during FGDS, biopsy of regional lymph nodes and changes hormonal levels can give the doctor an idea of ​​the complications that the presence of a tumor has caused in the patient’s body. If the prognosis for the patient is unfavorable even if the tumor is removed, then experts advise resorting to chemotherapy.

Most often, doctors use cytostatics to suppress the growth and development of tumors. But due to the large number side effects This method is recommended to be used only in case of emergency. In addition, its effectiveness is only 40%.

Symptomatic treatment

There are discomforts that are observed against the background of pathologies such as carcinoid syndrome and carcinoid tumor. Symptoms are usually closely related to the type of hormone the tumor produces. If it is serotonin, then the patient is prescribed antidepressants. If the main “aggressor” is histamine, then histamine receptor blockers come to the fore in therapy.

Were found synthetic analogues somatostatin, reducing symptoms by almost 90%. They suppress the production of several hormones at once and thereby secure a strong place in the treatment of this disease.

Surgical treatment

An important stage of treatment is removing the tumor from the body, searching for and resection of metastases, and ligating the liver arteries.

Per volume surgical intervention the location and size of the tumor, the presence or absence of metastases influences. Most often, surgeons remove the affected part of the organ and regional lymph node packages. As a rule, this is enough to permanently rid a person of carcinoid. IN advanced cases, When radical treatment impossible, the patient is offered hepatic artery embolization to relieve the symptoms of the disease.

Forecast

What can patients expect when diagnosed with carcinoid syndrome and carcinoid tumor? Hot flashes, heart palpitations and shortness of breath will likely remain with them for the rest of their lives, but will become less severe after treatment.

Medicine knows of cases where patients lived for more than ten years after surgery and symptomatic therapy. But on average their life expectancy is about 5-10 years. Tumors located in the lungs have the worst prognosis, and tumors located in the appendix have the best prognosis.

The main manifestations of carcinoid syndrome are diarrhea and hot flashes.

Hyperemia is the most common symptom which arises. Almost ninety percent of patients who have this disease show signs of hyperemia. There is an increase in temperature, the face and neck become red. Redness may occur due to emotional stress when drinking alcohol, physical work. Redness occurs suddenly and lasts from several minutes to several hours. At the same time, the patient’s blood pressure decreases, dizziness appears, and the heartbeat increases. Some doctors believe that with an increase in serotonin, bradykinin and substance P, redness occurs and these symptoms increase. Serotonin can cause diarrhea, histamine - wheezing, tachykinins - redness due to the fact that it dilates blood vessels.

Diarrhea – can occur with hyperemia or on its own. Doctors attribute diarrhea to the action of serotonin. Occurs in approximately 75% of patients. To reduce manifestations, use codeine phosphate every six hours, 15 mg, loperamide - the initial dose is prescribed 4 mg once, and then 2 mg, the maximum daily dose is 16 mg.

Heart problems – occur in half of patients with carcinoid syndrome. Carcinoid syndrome changes connective tissue in the pulmonary valve of the heart. Due to the fact that the valve is thickened, affected by carcinoid syndrome, the heart begins to poorly pump blood from the right stomach to the lungs and other parts of the body, this leads to heart failure. With the development of heart failure, ascites occurs, the liver enlarges, and the legs swell. Such symptoms are caused by prolonged and large quantities action of serotonin in the blood.

Carcinoid crisis is the most dangerous condition which may occur during surgery. A sharp drop in blood pressure, increased blood glucose levels, palpitations, bronchospasm. A carcinoid crisis can lead to the death of the patient, so before surgical intervention Somatostatin is used to prevent a crisis.

Wheezing – occurs due to bronchospasms as a result of the action of hormones released by the tumor.

Abdominal pain is common in patients with carcinoid syndrome. Metastases spread to the liver and pain occurs, or due to intestinal obstruction, since the tumor is more often found in the intestines.

The occurrence of carcinoid syndrome is determined by several reasons. Of significant importance are: slow growth of the primary tumor, massive metastasis and the size of metastases. However decisive role plays the extraportal location of the latter. All of these factors cause hypersecretion of serotonin and other biological active substances, which periodically enter the bloodstream and have a pathological effect on various organs and systems.

To the most characteristic group Vasomotor disorders include the so-called “flushing syndrome”, described in detail by Waldenstrom and Thorson. First of all, periodic “redness” of the face, shoulders, upper half of the body occurs, accompanied by a burning sensation, heat, palpitations, tachycardia, a feeling of weakness, sometimes profuse sweating. Color skin suddenly turns bright red, and then quite quickly changes to pink and goes back to a normal shade. Often spots of cyanosis (“spotted cyanosis”) remain on the skin against a background of general pallor. This attack lasts from 30 seconds to 10 minutes. During the day, the patient has from 5 to 30 such attacks.

Provoking factors for the “blushing syndrome” are: emotional and physical stress, abundant, hot food, drinking alcohol, defecation.

Over time, hyperemia of the skin can become permanent, cyanosis progresses, and patients remind their appearance patients with polycythemia (plethoric habitus). Telangiectasia sometimes occurs.

Some researchers try to explain the cyanotic phase of an attack of redness by a possible synergistic effect on vascular system serotonin and bradykinin, when simultaneously administered to rats, spasm of venules and retrograde spasm of blood in capillaries occurred (Weiner and Altura, 1967).

Attacks of redness with gastric carcinoids begin with bright red focal erythema with clearly defined boundaries. Apparently, in such patients, in addition to serotonin, significant amounts of histamine and 5-hydroxytryptophan, a precursor of serotonin, periodically enter the blood. The predominant formation of the latter by tumor tissue is due to a deficiency of decarboxylase, which ensures the synthesis of serotonin (Jones et al., 1968).

Carcinoid syndrome, which occurs with bronchial tumors, has specific features, attacks of redness are distinguished by the severity of their appearance, often accompanied by fever, lacrimation, runny nose, nausea and vomiting, hypotension and oliguria (Sandler, 1968). Such " carcinoid crises"(Kahil et al., 1964) may be caused by direct rapid entry of humoral agents into arterial system, bypassing the portal blood flow. “Rush syndrome” is sometimes accompanied by hypertension, as well as diarrhea and asthma attacks.

Diarrhea in some cases is combined with cramping pain in the abdomen, pronounced rumbling. This symptom is due to intestinal hyperperistalsis caused by increased secretion of serotonin, and possibly bradykinin. Both of these agents increase the tone of the smooth muscles of the bronchi, spasm them, which often leads to atypical attacks of bronchial asthma.

In addition to the “redness syndrome,” with a functioning carcinoid, changes of a different nature may be observed on the skin.

Some patients experience “pellagra-like lesions” associated with endogenous hypovitaminosis PP, caused by a relative lack of tryptophan for synthesis nicotinic acid in the intestines. Hyperkeratosis occurs, the skin becomes dry, peels, grayish-black areas of pigmentation form on the forearms and lower limbs, glossitis is noted.

Along with “pellagra-like lesions,” focal hyperpigmentation of a diffuse nature may be observed, caused by excessive deposition of serotonin destruction products in the skin. Skin metastases from carcinoid are sometimes painful.

In patients with carcinoid syndrome, in 40-50% of cases, tricuspid valve insufficiency and stenosis of the orifice are determined pulmonary artery(Sjoerdsma, 1956). The pathogenesis of these lesions remains unclear, but most researchers are proponents of the “biochemical theory” of their occurrence. The latter considers endocardial damage (mainly proliferative, not inflammatory in nature) in carcinoid syndrome as a result of hypersecretion of serotonin and other biologically active substances that primarily affect the endocardium and promote excessive growth of connective tissue.

Serotonin clearly increases tone arterial vessels lungs (Page, 1958), which creates additional stress on the right ventricle. The latter hypertrophies early, and then its myogenic dilatation quickly occurs with phenomena of stagnation in big circle blood circulation

In addition to hemodynamic factors, the origin of edema in carcinoid syndrome involves hypoalbuminemia due to a lack of tryptophan for protein synthesis, as well as a systematic increase venous pressure in the midst of bouts of “blushing.” The antidiuretic effect of serotonin also plays a certain role, and in some patients - increased concentration antidiuretic hormone.

Patients suffering from carcinoid syndrome for a long time become exhausted, and in some cases the weight remains.

Sometimes severe dizziness and transient visual disturbances caused by cerebral hypoxia occur.