A carcinoid is a slow-growing, potentially malignant tumor that can secrete hormone-active elements. This phenomenon belongs to the category of neuroendocrine neoplasms. A tumor is formed from the cells of the diffuse system, which are present in all internal organs. The bronchopulmonary apparatus takes the second place in the number of these structures, giving precedence to the digestive tract.
Lung carcinoid is a non-aggressive malignant tumor, which in the case of timely detection and the presence of a competent therapeutic regimen has a favorable prognosis.
Mechanism of occurrence
Neuroendocrine cells, on the basis of which pathological neoplasms are formed, appear even in the period of intrauterine development in the area of the nerve scallop, after which they move to the lungs. The tumor contains neurosecretory granules that produce biogenic amines - histamine, norepinephrine, prostaglandins, adrenaline, serotonin - and hormones.
Lung carcinoid belongs to the proximal type of cancer. With this type of pathology, the allocation of biologically active elements is very low or absent, there is no clear and detailed clinical picture of the disease.
Kinds
Given the cellular structure, such cancer is classified into two categories.
A typical lung carcinoid is a highly differentiated neuroendocrine abnormality. The neoplasm is formed by the smallest cells with large nuclei and granules that produce secretions. These structures, in turn, also divide the disease into classes:
- trabecular - atypical cells are delimited by special fibrous layers;
- adnocarcinoma - the neoplasm is localized on the mucous membrane, its surface is covered with a prismatic layer of the epithelium, and its structure is predominantly glandular;
- undifferentiated - it is formed in the epithelial layer, spreads quite quickly and provokes the onset of metastasis;
- mixed.
Atypical lung carcinoid occurs in only 10-30% of all cases of the disease. This tumor has an aggressive nature, spreads rapidly, has increased hormonal activity, metastasizes throughout the body. Such a cancer resembles an infiltrate with a disorganized structure, which consists of large pleomorphic elements. In the lungs with this type of pathology, necrotic foci may appear.
Causes
As you know, reliable causes of various types of cancer are still undetected, and lung carcinoid is no exception. But experts found several predisposing conditions that may well provoke the nucleation of a tumor in the respiratory system. These should include, first of all:
- genetic predisposition;
- severe stages of viral infections;
- chronic poisoning of the body with alcohol and tobacco.
Clinical picture
Lung carcinoid is diagnosed in equal proportions in both men and women. People aged 10 to 80 years are affected. A malignant tumor is localized most often in the central zone of the organ, near large bronchi and a little less often in the parenchyma.
Severe symptoms usually begin with relapses of pneumonia. The victims have attacks of dry unproductive cough, sputum excretion is minimal, with clots or streaks of blood. Symptoms of pathology are similar to obstruction of the bronchi and bronchial asthma, which is characterized by a sensation of suffocation. In parallel with the carcinoid, subsidence of the damaged lobe of the lung develops.
In every third patient, the defect is completely asymptomatic. Often, a neoplasm is detected absolutely by accident during a preventive examination of the body.
Associated pathologies
Along with cancer, ectopic syndrome is progressing, which is due to increased production of hormones produced by tumor cells. Symptoms of this disease are:
- moon-shaped face shapes;
- weight loss of legs and arms against the background of loss of muscle mass;
- acne eruptions;
- scarlet blush on the cheeks with a slight bluish tint;
- excessive fat in the chest, neck, abdomen and face;
- stretch marks in the buttocks, abdomen and hips.
It is noteworthy that with this pathology, injuries on the skin heal very slowly. Representatives of the weaker sex have facial vegetation on the male type. The bones become too fragile. Over time, blood pressure indicators increase.
In some cases, patients have functional disorders in the digestive tract in the form of diarrhea and paroxysmal pain in the abdominal cavity. Hot flashes occur, carcinoid heart ailments arise.
Distant metastases are most often detected in the tissues of the liver.
Diagnostics
If lung cancer is suspected, the patient is examined using instrumental and laboratory techniques. First of all, a clinical analysis of urine and blood is performed. Then, the organs of the chest cavity are carefully examined.
Lung carcinoid is initially detected on an x-ray. To obtain more information, the patient is sent to computed tomography, which clearly demonstrates pathological changes in organ tissue in several projections. In addition, the lymphatic and skeletal system of the body is examined.
If a tumor is detected, bronchoscopy is performed to take the biological material for histology. A special smear is made from tissue samples, which is examined under a microscope - this determines the nature of the tumor.
To diagnose the disease, it is also very important to detect the presence of hormones and biologically active elements produced by cancer cells. For this, minor doses of histamine-like medications are introduced into the patient's body. If the patient has a reaction of a vegetative type - arrhythmia, hot flashes in the head and neck, colic in the abdomen, you can diagnose a functioning carcinoid.
Additionally, other diagnostic methods can be used:
- Magnetic resonance imaging;
- scintigraphy;
- positron emission tomography.
Lung carcinoid treatment
The main therapeutic measure used in relation to patients with this diagnosis is the surgical removal of damaged tissue. To do this, an anatomical resection is performed - a segment or a lobe of the lung is excised, and the parenchyma remains intact. In the case of surgery, relapse pathologies are extremely rare. Such treatment gives a positive result.
If the carcinoid penetrated the bronchus, a resection of the damaged area of the tree and suturing of special threads are carried out. This is necessary to align the cartilage.
If cancer is detected directly in the lung, lymph nodes and fiber in the mediastinal area are removed.
Together with surgical intervention, the patient is recommended chemotherapy, radio wave exposure, the use of potent immune medications. With the help of drugs, the patient's hormonal background is corrected.
Further prognosis for lung carcinoid
This disease is not considered dangerous. The five-year life expectancy for a typical lung carcinoid is about 90-100%. But with an atypical course of pathology, the situation is much worse. In this case, hardly 50-60% of patients can talk about five-year survival. The threshold of ten-year life expectancy reaches only 30%.
After surgery, even when cancer cells remain along the resection line, the neoplasm provokes relapses extremely rarely. Every fourth patient may well live up to 25 years.
Forecasts for atypical lung carcinoid, as already mentioned, are not so rosy. In the case of metastatic lymph nodes, the five-year survival rate reaches only 20%. That is why when identifying an atypical lung carcinoid, therapy involving the preservation of the damaged organ is simply not practical.