Carcinoid
Last reviewed: 23.04.2024
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Carcinoid (argentaffinoma, chromaffinoma, carcinoid tumor, tumor of APUD-system) is a rare neuroepithelial hormone-active tumor producing excess serotonin. Carcinoids are formed in intestinal crypts from intestinal argentaffinocytes (Kulchitsky cells), which belong to the diffuse endocrine system.
Tumor occurs at a frequency of 1: 4000 population, and according to pathological anatomical studies, the incidence of carcinoid tumors is 0.14%. Carcinoid tumors can be found in almost all organs and tissues. Carcinoid is 5-9% of all tumors of the gastrointestinal tract. According to AV Kalinin (1997), the carcinoid is localized in the appendix in 50-60% of cases, in 30% in the small intestine. Significantly less often, carcinoma is localized in the pancreas, bronchi, gall bladder, ovaries and other organs.
The greatest amount of serotonin produces carcinoids, localized in the skinny, iliac and right half of the large intestine. When the carcinoid is localized in the stomach, pancreas, duodenum, bronchi, the amount of serotonin produced by the tumor is much less.
For the first time, O. Lubarsch in 1888 gave a pathoanatomical description of tumor formations originating from these cells, subsequently called argetaffin.
The name "carcinoid" was suggested by S. Oberndorfer in 1907 to designate an intestinal tumor resembling a cancerous tumor (carcinoma), but differing from it by a lesser malignancy. These tumors account for 0.05-0.2% of all malignant neoplasms and 0.4-1% of all gastrointestinal neoplasms. About 1-3% of them are located in the large intestine, in some cases - in the appendix. So, according to J. Arid, in 5-8% of appendix processes removed from chronic appendicitis, argentaffinoma is histologically detected. According to the statistics of FW Sheely and MN Floch (1964), covering 554 descriptions of malignant tumors of the small intestine, carcinoids were observed in 65 cases (11.7%), which were more often localized in the distal segment of the ileum. Carcinoids of the rectum are described. There are these tumors in the bronchi, pancreas, liver, gall bladder, prostate gland. They are at any age, occasionally in children and youth (the average age of patients with this pathology is 50-60 years), approximately equally common in men and women.
Carcinoids are relatively slowly growing tumors. Therefore, due to the long absence of local symptoms, first explained by the small size of the tumors and their slow growth, the carcinoids were for a long time considered "almost innocent extensions of the intestinal mucosa, an accidental finding during an operation or an autopsy." Later, malignancy of the tumor was proved, which, when localized in the small intestine, gives metastases in 30-75% of cases. In carcinoids of the large intestine, metastasis is detected in 70% of cases; The 5-year survival rate is 53%. The most common are single and multiple carcinoid metastases in the regional lymph nodes, peritoneum, various parts of the gut and liver.
The tumor, as a rule, is located in the submucosal layer of the intestine and grows in the direction of the muscular and serous layer; its dimensions are usually small, the diameter often varies from a few millimeters to 3 cm. On the cut, the tumor tissue has a yellow or gray-yellow color, is characterized by a high content of cholesterol and other lipids, dense. With carcinoid often thickening and shortening of the valves of the tricuspid valve and the valve of the pulmonary artery, and as a consequence - valve vice, muscular hypertrophy and dilatation of the right ventricle.
Histological examination determines the characteristic structure of the carcinoid tumor. In the cytoplasm of cells, birefringent lipids and, most notably, grains containing serotonin, detected histologically by chromaffin and argentaffin reactions.
Causes of carcinoid development
The cause of carcinoid, as well as of other tumors, is still unclear. It was noted that many symptoms of the disease are due to hormonal activity of the tumor. With the greatest degree of certainty, significant isolation by cells of a tumor of serotonin (5-hydroxytryptamine), the product of the conversion of the amino acid tryptophan, has been demonstrated, and in the blood its content reaches 0.1-0.3 μg / ml. Under the influence of monoamine oxidase, the bulk of serotonin is converted to 5-hydroxyindolylacetic acid, excreted in the urine. In the urine, the content of the final product of its conversion - 5-hydroxyindolylacetic acid (5-GOIUK) - is sharply increased in carcinoid and in most cases is 50-500 mg (at a rate of 2-10 mg).
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Symptoms of carcinoma
The main symptoms of carcinoid - attacks of blood tides in the face, neck, and chest - while suddenly blushing the face, neck, neck, upper body. In these places the patient feels a burning sensation, a feeling of heat, numbness. Many patients at high tide have reddening of the eyes (conjunctiva injection), increased tearing, hypersalivation, edema of the face, tachycardia appears; possibly a significant decrease in blood pressure. At the onset of the disease, tides are rare (1-2 times in 1-2 weeks or even in 1-3 months), later they become daily and can disturb patients 10-20 times a day. The duration of the tides ranges from one to 5-10 minutes.
Diagnosis of carcinoma
Laboratory studies in the vast majority of cases confirm the elevated blood 5-hydroxytryptamine in the blood and 5-hydroxyindolylacetic acid in urine, the latter being 12 mg / day suspicious, and more than 100 mg / day is considered a reliable sign of the carcinoid. It should be borne in mind that reserpine, phenatiazine, Lugol's solution and other medications, as well as eating a large number of bananas, a mature tomato increases the serotonin content in the blood and the final product of its metabolism - 5-hydroxyindolylacetic acid in the urine, and aminazine, antihistamines and other medicinal drugs - lower. Therefore, when carrying out laboratory tests, one should keep in mind these possible effects on the results of the analyzes obtained.
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Treatment of carcinoid
Surgical treatment - resection of the intestine with a radical removal of the tumor and metastases, if any. Carcinoids are thick, more often than the rectum, can also be removed through the endoscope or transanal. Symptomatic therapy consists in the appointment of blockers of a- and beta-adrenergic receptors (anaprilin, phentolamine, etc.); less effective corticosteroids, aminazine and antihistamines.
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Prognosis with carcinoid
The prognosis for timely diagnosis and surgical removal of the tumor is relatively favorable, it is better than with other types of malignant tumors.
A feature of carcinoid is a slow growth, so that the average life expectancy of patients even without treatment is 4-8 years or more. Death can come from multiple metastases and cachexia, heart failure, intestinal obstruction.