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Carcinoid: diagnosis
Last reviewed: 23.04.2024
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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.
The diagnosis is confirmed by the results of a histological examination of biopsy specimens. When stained with hematoxylin and eosin, small polygonal or round cells with basophilic nuclei are detected. The cells are grouped into rosettes, nests and give an argyrophilic reaction in a special color.
Radiographic examination of the tumor is difficult to detect because of its small size and eccentric growth.
Tumor metastases in the liver are recognized quite easily with the help of ultrasound and computed tomography of the liver. Carcinoid is a malignant tumor, but grows slowly and late metastasizes. The most typical metastases in regional lymph nodes, the liver, possibly metastasis in the cervical lymph nodes, lungs, brain, bones, ovaries.
An increase in serotonin in the blood and an increase in the urinary excretion of its metabolite 5-hydroxyindoleacetic acid (5-GOIUK) - these indicators are especially dramatically increased during a seizure of blood. Before the study, it is necessary to cancel the medicinal preparations for 3 days (especially reserpine - it increases the serotonin content in the blood, phenothiazine compounds, diuretics) and exclude from the diet products containing serotonin and tryptophan (bananas, pineapples, walnuts, avocados, plums, currants, tomatoes , eggplant, cheddar cheese). The upper level of normal urinary excretion of 5-GOIUK is 10 mg / day. Excretion in the urine of 5-GOIUK 10-25 mg / day allows to suspect the presence of carcinoid, and the value more than 25 mg / day undoubtedly indicates the existence of carcinoid. If the results are unconvincing, a test with reserpine is performed. Reserpine promotes the release of serotonin from brain cells and peripheral depots and prevents the binding of serotonin in platelets. In healthy people, after taking reserpine, the excretion of 5-GOIUK with urine increases only in the first hours after taking reserpine, and in case of carcinoid syndrome it increases significantly in comparison with the initial one and remains elevated for several hours and even a day.
In some cases, it is possible to detect the presence of intestinal carcinoid with colonoscopy (with localization in the large intestine), inoscopy (with localization in the jejunum), intestinal fluoroscopy, magnetic resonance imaging.
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