Carcinoid

Description:

Carcinoid occurs among epithelial tumors of a small bowel most often and can be in any its department. Most often carcinoid is in a worm-shaped shoot (45,9%), ileal (27,9%) and a straight line (16,7%) guts.

Carcinoid reasons:

Carcinoid develops from argyrophil cells of intestinal crypts and belongs to the hormonal and active tumors producing serotonin, a histamine, bradykinin and prostaglandins. The tumor of usually small size (about 1,5 cm), is located in a submucosa, the mucous membrane over it is not changed. The ulceration, a stenosis and bleeding develop preferential and malignancy stages. Distinguish five histologic types of carcinoid. Vtrechatsya more often type A — knotty (22,6%) and type B — trabecular, or tape-like (21%) forms, is more rare — type C — tubular with acinar or rozetkoobrazny structures (3,2%) and the type D — low-differentiated or typical (9,2%). Approximately in half of cases (43,5%) the mixed forms are observed. Argentaffin carcinoid belongs preferential to type, argyrophil — to the mixed type. Inactive forms of carcinoid are observed at type B and the mixed type. All carcinoids are potentially malignant. The risk of a malignancy grows in process of increase in the sizes of a tumor. Carcinoid contains a large amount of serotonin at high activity of a dopadekarboksilaza and low activity of an aminooxidase. In rova serum the content of serotonin, and in urine — a product of an aspad of serotonin (5-oxyindolacetic acid) considerably increases. The serotonin which is formed in tumoral fabric expands capillaries, causing hypostasis and a bronchospasm. The liver affected with tumor metastasises contains the increased amount of kallikrein — enzyme by means of which of a kininogen of a blood plasma the bradykinin having ability to expand vessels, to cause inflows, spasms of bronchial tubes and intestines is formed. Inflows cause also catecholamines which promote kallikrein release. The pathogeny of development of a cardiopathy, defeat of the trikuspidapny valve and a pulmonary trunk is explained by spastic influence of a bradikininaa of serotonin on the muscular device of bronchial tubes and vessels.

Carcinoid symptoms:

Clinical symptoms of carcinoid are caused as the tumor (partial or full obstruction, bleedings), and emission in blood of a large amount of serotonin and bradikinin. Attacks are often provoked by alcohol intake, emotions and the use of a large number of food as all these factors cause increase in level of catecholamines in blood. The classical carcinoid syndrome is observed seldom and appears at carcinoid metastasises in a liver as in the affected liver serotonin metabolism is broken by hepatic monoamine oxidase. Very seldom the so-called atypical carcinoid syndrome meets a hyper dysinsulinism, hyperproduction of AKTG, histamine and prostaglandins.
Clinically carcinoid syndrome is characterized by four main symptoms.
1. Skin symptoms: inflows, long cyanosis, teleangiectasias.
2. Bronchopulmonary symptoms: bronchial asthma, tachypnea, hyperpnea.
3. Cordial symptoms: cardiopathy, stenosis of a pulmonary trunk, insufficiency of the tricuspid valve, right ventricular insufficiency.
4. Gastrointestinal symptoms: colicy pains, diarrhea, impassability of intestines. Before all gastrointestinal symptoms are observed. The patient has sudden colicy pains in a stomach (as gripes) which are followed by loud rumbling and a plentiful diarrhea with slime impurity. Further perhaps gradual increase of symptoms of enteric impassability. There are sudden attacks of suffocation with a sharp dermahemia, heartbeat later. Skin gains cyanotic-red color, the set of teleangiectasias develops. From cardiovascular system signs of right ventricular insufficiency attract attention. Cyanosis, expanded cervical veins, tachycardia concern to them. At a tool research reveal a stenosis of a pulmonary trunk, insufficiency of the tricuspid valve, developing as a result of endothelium fibrosis under the influence of serotonin. Often bronchial asthma joins. At a research of abdominal organs the increased dense liver attracts attention much.
The diagnosis of carcinoid is based on definition in serotonin blood, and in urine — 5-oxyindolacetic acid. The tumor is more often localized in a worm-shaped shoot, an ileocecal corner, a rectum, but can be in a stomach and other departments of thin and thick guts. At X-ray inspection the accelerated barium sulfate passage on a small bowel comes to light and only at increase in the sizes of a tumor up to 1 — 2 cm and more it can be found by means of radiological and endoscopic methods. The histologic research of bioptat during endoscopy seldom yields a positive take because the tumor, as a rule, is located in a submucosa.
Differential diagnosis is carried out with other malignant and benign tumors of a small bowel, and also insulinomy, somatostatinomy and other gormonalnoaktivny tumors. Verification apudy is accompanied by great difficulties. Tumors have the small sizes, their density almost does not differ from density of the struck body (most often a pancreas). Seldom tumoral fabric is located in a pancreas or a small bowel on a considerable extent, forming accumulations of the cells producing hormones. In this case topical diagnosis is extremely difficult and based on a research of the blood samples received during the selection angiography with introduction of the probe to a pankreatoduodenalny vein.

Carcinoid treatment:

After diagnosis of carcinoid the patient should appoint clinical nutrition, it is necessary to exclude products with the increased contents from a diet serotonin. These are first of all nuts, bananas, pineapples, etc. Apply surgical and conservative methods to treatment of carcinoids. Surgical receptions consist in excision of a tumor or removal of body depending on its sizes and degree of a zlokachestvennost. In the postoperative period development of carcinoid crisis with cardiovascular insufficiency and paresis of intestines is possible. It is possible to stop crisis intravenous administration of a sandostatin (октреотид) in a dose 0,1 — 0,5. Conservative actions assume appointment of antagonists of serotonin  (метилсергид, dezerit, периактинол and нуран). Metilsergid also dezerit appoint 1 - 3 mg a day, and периактинол and нуран - 6 - 10 mg a day. The Serotoninovy syndrome at carcinoid can be suppressed by somatostatin. The drug is administered subcutaneously in a daily dose of 0,2 — 0,6 mg, distributing it on 2 — 3 times. The symptomatic treatment includes use of anti-diarrheal drugs (имодиум), niacin drugs for reduction of symptoms of a pellagra. As the indication to chemotherapy serves the expressed carcinoid syndrome, resistant to treatment by usual pharmacological means. Existence of one of predictively adverse signs (the release of 5-oxyindolacetic acid with urine exceeding 150 mg/days or development of carcinoid damage of heart) is such indication. Apply рептозоцин (500 mg on 1 sq.m of a body surface) and 5-ftoruratsit (400 mg on 1 sq.m) з a current of 5 days. The cycles are repeated with an interval of 6 weeks.
The forecast at high-quality carcinoid favorable. After operation there occurs recovery. At malignant carcinoid from an otdalennykma metastasises the forecast bad though in some cases combined (operational and chemotherapeutic) treatment allows to prolong the patient's life up to 3 years and more.