Organs of the anterior mediastinum. Mediastinal organs

There are several approaches to dividing our body into sections. Clear boundaries of organs and systems, as well as their totality, help doctors navigate the body more accurately, prescribing treatment, describing any failures and pathologies. At the same time, doctors, regardless of their profile, use the same terms to refer to specific parts of the body. So the zone that is localized in the middle and in the upper part of the body can be called the sternum. However, medical specialists call it the mediastinum. Today we will talk about the mediastinum, tumors of the mediastinum, nodes of the mediastinum, what is its anatomy, where is it located.

Structure

In order to more accurately describe the location of pathologies and plan correction methods, the mediastinum is divided into upper and lower, as well as anterior, posterior and middle.

The anterior part of this area is limited on the front side by the sternum, and behind - by the brachiocephalic vessels, as well as the pericardium and the brachiocephalic trunk. Inside this space, the thoracic veins pass, in addition, the thymus is located in it, in other words, the thymus gland. It is in front of the mediastinum that the thoracic artery and lymph nodes go. The middle part of the area under consideration includes the heart, hollow, brachiocephalic, phrenic, pulmonary veins. In addition, it includes the brachiocephalic trunk, aortic arch, trachea, main bronchi, pulmonary arteries. As for the posterior mediastinum, it is limited to the trachea, as well as the pericardium from the frontal area, and the spine from the back side. This part includes the esophagus and the descending aorta, in addition, it includes the semi-unpaired and unpaired veins, the thoracic lymphatic duct. The posterior mediastinum also contains lymph nodes.

The upper mediastinal zone consists of all anatomical structures located above the upper border of the pericardium, represented by the superior aperture of the sternum, as well as a line passing from the angle of the chest and the intervertebral disc Th4-Th5.

As for the lower mediastinum, it is limited by the upper edges of the diaphragm and pericardium.

Tumors of the mediastinum

In the area of ​​the mediastinum, various tumor-like formations can develop. At the same time, neoplasms of this organ include not only true formations, but also those cysts and tumor-like ailments that have an excellent etiology, location, and other course of the disease. Any neoplasm of such a plan originates from tissues of different origin, they are united exclusively by the place of localization. At the same time, doctors consider:

Neoplasm Clinic

Tumor formations are usually found in representatives of the young and middle age groups, regardless of gender. As practice shows, diseases of the mediastinum often do not indicate themselves in any way, they can only be detected during preventive studies. At the same time, there are some symptoms that can indicate such violations and which you need to pay attention to.

So, tumor formations inside the mediastinum often make themselves felt with non-intense painful sensations that can be given towards the neck, shoulder area and between the shoulder blades. In the event that the formation grows inside the borderline sympathetic trunk, the patient's pupils dilate, drooping of the eyelid and retraction of the eyeball may be observed.

The defeat of the recurrent laryngeal nerve often makes itself felt hoarseness in the voice. The classic symptoms of tumor formations are pain in the chest area, as well as a feeling of heaviness in the head. In addition, shortness of breath, cyanosis, swelling of the face, and violations of the passage of food through the esophagus may occur.

If diseases of a tumor nature reach an advanced stage of development, the patient experiences a noticeable increase in body temperature, as well as severe weakness. In addition, there is arthralgia, a failure in the rhythms of the heart, some swelling of the extremities.

Lymph nodes of the mediastinum

As mentioned above, there are many lymph nodes inside the mediastinum. The most common lesion of these organs is lymphadenopathy, which can develop against the background of metastases of carcinoma, lymphoma, as well as some non-tumor diseases, for example, sarcoidosis, tuberculosis, etc.

In addition to changing the size of the lymph nodes, lymphadenopathy makes itself felt with fever, as well as excessive sweating. In addition, there is a strong weight loss, hepatomegaly, splenomegaly develops. Diseases provoke frequent infection of the upper respiratory tract in the form of tonsillitis, various types of tonsillitis and pharyngitis.

In some cases, lymph nodes can be affected in isolation, and sometimes tumors grow into other organs.

Elimination of tumor diseases and other problems with the mediastinum is carried out according to generally accepted standards of therapeutic effects.

All mediastinal tumors are an urgent problem for modern thoracic surgery and pulmonology, since such neoplasms are diverse in their morphological structure, they can be initially malignant or prone to malignancy. In addition, they always carry a potential risk of possible compression or germination into vital organs (airways, vessels, nerve trunks or esophagus) and it is technically difficult to remove them surgically. In this article, we will introduce you to the types, symptoms, methods for diagnosing and treating mediastinal tumors.

Tumors of the mediastinum include a group of neoplasms located in the mediastinal space with different morphological structure. They are usually formed from:

• tissues of organs located within the mediastinum;
• tissues located between the organs of the mediastinum;
• tissues that appear with violations of intrauterine development of the fetus.

According to statistics, neoplasms of the mediastinal space are detected in 3-7% of cases of all tumors. At the same time, about 60-80% of them are benign, and 20-40% are cancerous. Such neoplasms are equally likely to develop in both men and women. Usually they are detected in people 20-40 years old.

A bit of anatomy

The mediastinum is located in the middle part of the chest and is limited by:

• sternum, costal cartilages and retrosternal fascia - in front;
• prevertebral fascia, thoracic spine and rib necks - behind;
• the upper edge of the handle of the sternum - from above;
• sheets of the medial pleura - on the sides;
• diaphragm from below.

In the region of the mediastinum are:

• thymus;
• esophagus;
• arch and branches of the aorta;
• upper sections of the superior vena cava;
• subclavian and carotid arteries;
• The lymph nodes;
• brachiocephalic trunk;
• branches of the vagus nerve;
• sympathetic nerves;
• thoracic lymphatic duct;
• tracheal bifurcation;
• pulmonary arteries and veins;
• cellular and fascial formations;
• pericardium etc.

In the mediastinum, to indicate the localization of the neoplasm, experts distinguish:

• floors - lower, middle and upper;
• departments - anterior, middle and posterior.

Classification

All tumors of the mediastinum are divided into primary, i.e., initially formed in it, and secondary - arising as a result of metastasis of cancer cells from other organs outside the mediastinal space.

Primary neoplasms can form from various tissues. Depending on this fact, the following types of tumors are distinguished:

• lymphoid - lympho- and reticulosarcomas, lymphogranulomas;
• thymomas - malignant or benign;
• neurogenic - neurofibromas, paragangliomas, neurinomas, ganglioneuromas, malignant neuromas, etc.;
• mesenchymal - leiomyomas, lymphangiomas, fibro-, angio-, lipo- and leiomyosarcomas, lipomas, fibromas;
• disembryogenetic - seminomas, teratomas, chorionepithelioma, intrathoracic goiter.

In some cases, pseudotumors can form in the mediastinal space:

• on large blood vessels;
• enlarged conglomerates of lymph nodes (with Beck's sarcoidosis or);
• true cysts (echinococcal, bronchogenic, enterogenic cysts or coelomic cysts of the pericardium).

As a rule, retrosternal goiter or thymomas are usually detected in the upper mediastinum, on average - pericardial or bronchogenic cysts, in the anterior - teratomas, lymphomas, thymomas, mesenchymal neoplasms, in the posterior - neurogenic tumors or enterogenic cysts.

Symptoms

As a rule, neoplasms of the mediastinum are detected in people 20-40 years old. During the course of the disease, there are:

• asymptomatic period - a tumor can be detected by chance during an examination for another disease or on fluorography images performed during routine examinations;
• the period of pronounced symptoms - due to the growth of the neoplasm, there is a violation in the functioning of the organs of the mediastinal space.

The duration of the absence of symptoms largely depends on the size and location of the tumor process, the type of neoplasm, the nature (benign or malignant), the growth rate and the relationship to the organs located in the mediastinum. The period of pronounced symptoms in tumors is accompanied by:

• signs of compression or invasion of the organs of the mediastinal space;
• specific symptoms characteristic of a particular neoplasm;
• general symptoms.

As a rule, with any neoplasm, the first sign of the disease is pain that occurs in the chest area. It is provoked by sprouting or compression of nerves or nerve trunks, is moderately intense and can be given to the neck, the area between the shoulder blades or shoulder girdle.

If the tumor is located on the left, then it causes, and with compression or germination of the borderline sympathetic trunk, it often manifests itself as Horner's syndrome, accompanied by redness and anhidrosis of half of the face (on the side of the lesion), drooping of the upper eyelid, miosis and enophthalmos (retraction of the eyeball in the orbit). In some cases, with metastatic neoplasms, pain in the bones appears.

Sometimes a tumor of the mediastinal space can compress the trunks of the veins and lead to the development of the syndrome of the superior vena cava, accompanied by a violation of the outflow of blood from the upper body and head. With this option, the following symptoms appear:

• sensations of noise and heaviness in the head;
• chest pain;
• dyspnea;
• swelling of the veins in the neck;
• increased central venous pressure;
• swelling and bluishness in the face and chest.

With compression of the bronchi, the following symptoms appear:

• cough;
• difficulty breathing;
• stridor breathing (noisy and wheezing).

When the esophagus is compressed, dysphagia appears, and when the laryngeal nerve is compressed, dysphonia appears.

Specific Symptoms

With some neoplasms, the patient has specific symptoms:

• with malignant lymphomas, itching is felt and sweating appears at night;
• with neuroblastomas and ganglioneuromas, the production of adrenaline and noradrenaline increases, leading to an increase in blood pressure, sometimes tumors produce a vasointestinal polypeptide that provokes diarrhea;
• with fibrosarcomas, spontaneous hypoglycemia (lowering blood sugar levels) can be observed;
• with intrathoracic goiter, thyrotoxicosis develops;
• with thymoma, symptoms appear (in half of patients).

General symptoms

Such manifestations of the disease are more characteristic of malignant neoplasms. They are expressed in the following symptoms:

• frequent weakness;
• feverish state;
• pain in the joints;
• pulse disorders (brady or tachycardia);
• signs.

Diagnostics

Pulmonologists or thoracic surgeons can suspect the development of a mediastinal tumor by the presence of the symptoms described above, but a doctor can make such a diagnosis with accuracy only on the basis of the results of instrumental examination methods. To clarify the location, shape and size of the neoplasm, the following studies may be prescribed:

• radiography;
• chest X-ray;
• x-ray of the esophagus;
• polypositional radiography.

A more accurate picture of the disease and the prevalence of the tumor process can be obtained:

• PET or PET-CT;
• MSCT of the lungs.

If necessary, some endoscopic examination methods can be used to detect tumors of the mediastinal space:

• bronchoscopy;
• videothoracoscopy;
• mediastinoscopy.

With bronchoscopy, specialists can exclude the presence of a tumor in the bronchi and the germination of the neoplasm in the trachea and bronchi. During such a study, a transbronchial or transtracheal tissue biopsy may be performed for subsequent histological analysis.

At a different location of the tumor, an aspiration puncture or transthoracic biopsy can be performed under X-ray or ultrasound control to collect tissues for analysis. The most preferred method for taking biopsy tissue is diagnostic thoracoscopy or mediastinoscopy. Such studies allow the sampling of material for research under visual control. Sometimes a mediastinotomy is performed to take a biopsy. With such a study, the doctor can not only take tissue for analysis, but also conduct an audit of the mediastinum.

If the examination of the patient reveals an increase in the supraclavicular lymph nodes, then he is prescribed a prescaled biopsy. This procedure consists in excision of palpable lymph nodes or an area of ​​fatty tissue in the area of ​​the angle of the jugular and subclavian veins.

With the likelihood of developing a lymphoid tumor, the patient undergoes a bone marrow puncture followed by a myelogram. And in the presence of superior vena cava syndrome, CVP is measured.

Treatment

Both malignant and benign tumors of the mediastinum should be removed surgically as soon as possible. This approach to their treatment is explained by the fact that they all carry a high risk of developing compression of surrounding organs and tissues and malignancy. Surgery is not indicated only for patients with malignant neoplasms in advanced stages.

Surgery

The choice of method of surgical removal of the tumor depends on its size, type, location, the presence of other neoplasms and the patient's condition. In some cases, and with sufficient equipment of the clinic, a malignant or benign tumor can be removed using minimally invasive laparoscopic or endoscopic techniques. If it is impossible to use them, the patient undergoes a classic surgical operation. In such cases, a lateral or anterolateral thoracotomy is performed to access the tumor with its unilateral localization, and with a retrosternal or bilateral location, a longitudinal sternotomy is performed.

For patients with severe somatic diseases, transthoracic ultrasonic aspiration of the tumor may be recommended to remove tumors. And in the case of a malignant process, an extended removal of the neoplasm is performed. At advanced stages of cancer, palliative excision of tumor tissues is performed to eliminate compression of the organs of the mediastinal space and alleviate the patient's condition.

Radiation therapy

The need for radiation therapy is determined by the type of neoplasm. Irradiation in the treatment of tumors of the mediastinum can be prescribed both before surgery (to reduce the size of the neoplasm) and after it (to destroy all cancer cells remaining after the intervention and prevent relapses).

Front wall of the anterior mediastinum is the sternum, covered with intrathoracic fascia, the back is the anterior wall of the pericardium. On the sides, it is limited by the sagittal spurs of the intrathoracic fascia and the anterior transitional folds of the pleura. In this area, the transitional folds of the pleura lie very close to each other, often connecting with a ligament.

Anterior mediastinum, extending from above from the horizontal plane at the level of the tracheal bifurcation, and from below to the diaphragm, is also called the retrosternal (retrosternal) cellular space.

The contents of the space are fiber, internal thoracic vessels and anterior lymph nodes of the mediastinum. A.et v. thoracicae intemae up to level II of the costal cartilages are located between the pleura and the intrathoracic fascia, below the latter they perforate and lie anterior to it, and below the III ribs lie on the sides of the sternum (up to 2 cm from the edges) between the internal intercostal muscles and the transverse muscle of the chest.

At the same level front transitional folds of the pleura begin to diverge to the sides (more on the left), forming the lower interpleural triangle.

On the lower (diaphragmatic) wall of the anterior mediastinum you can see two sternocostal triangles between the pars stemalis and pars costalis of the diaphragm, where the intrathoracic and intra-abdominal fascia are adjacent to each other.

From the fibrous pericardium to the intrathoracic fascia in the sagittal direction pass the upper and lower sternopericardial ligaments, ligamenta sternopericardiaca.

AT tissue of the anterior mediastinum located prepericardial lymph nodes. They are connected through the intercostal space with the lymphatic vessels of the mammary gland, as a result of which they are quite often affected by metastases in breast cancer.

is a group of malignant tumors that originate from organs and tissues located in this area. The mediastinum is bounded laterally by the lungs, in front and behind by the sternum, spinal column and ribs, and below by the diaphragm. Large blood and lymphatic vessels are located here, so mediastinal cancer often occurs secondary due to metastasis from other parts of the body. The mediastinal organs themselves also serve as a source of neoplasm - it leads to the proliferation of cells of the thymus, trachea, esophagus, bronchi, nerve trunks, pericardium, adipose or connective tissue. There are also atypia, the cytology of which resembles embryonic tissues.

The relevance of the problem is that the average age of patients is 20-40 years. It occurs in adolescents (girls and boys), and even in children. The elderly are also affected by this disease. The incidence in Russia is 0.8-1.2%, or one fifth of all tumors in this area. Epidemiology shows that it occurs in both men and women around the world, although there are epidemiologically unfavorable areas. For example, female thyrotoxic goiter is common in mountainous regions, where the incidence of cancer in the anterior mediastinum is also high.

It is possible to find out how dangerous education is only by histological examination, which makes it difficult to differentiate. Even a benign character does not exclude malignancy. Mediastinal cancer is deadly, the prognosis is unfavorable, mortality is high, and not only because of the difficulties of diagnosis, but also because it is often inoperable due to the involvement of large vessels, nerves, and vital organs. However, this does not mean that it is incurable - there is a chance to survive, you need to continue to fight.

Types of mediastinal cancer

The classification of mediastinal cancer is difficult, since there is a description of more than 100 varieties of neoplasms, including primary and secondary types.

According to the cytological picture, the following types are distinguished:

• . small cell - rapidly progressing, as it metastasizes hematogenously and lymphogenously;
• . squamous - develops for a long time, arises from mucous membranes (pleura, pericardium, vessel walls);
• . embryonic, or germiogenic - is formed from embryonic membranes due to pathologies of fetal embryogenesis;
• . poorly differentiated.

Forms are distinguished by origin and localization.:

• . angiosarcoma;
• . liposarcoma;
• . synovial sarcoma;
• . fibrosarcoma;
• . leiomyosarcoma;
• . rhabdomyosarcoma;
• . malignant mesenchymoma.

The international TNM classification is used to determine the prevalence of the disease.

Mediastinal cancer, symptoms and signs with a photo

The very beginning of mediastinal cancer is asymptomatic, which is expressed by the absence of complaints from the patient until the size of the tumor increases. You should pay attention to weakness, fatigue, weight loss, which is up to 10-12 kilograms in 1-2 months.

With the primary involvement of the bronchi and trachea, the disease is expressed by respiratory failure (shortness of breath, cough). In the early stages of pericardial damage, the first obvious manifestations are arrhythmia, bradycardia, and frequent pulse. The pain syndrome is pronounced, it hurts behind the sternum, pain and burning are localized from the side of development and radiate to the back to the shoulder blade.

External, visible changes on the body occur if the central veins are compressed. With pressure on the superior vena cava, cyanosis is observed, it also appears when the tumor compresses the lungs and the tracheobronchial tree. Red spots on the skin, face, dermographism, increased sweating, drooping of the eyelid, dilated pupil, retraction of the eyeball - a characteristic unilateral symptomatology of the germination of the sympathetic trunk.

The initial signs of germination of the recurrent laryngeal nerve are hoarseness of voice, a change in timbre; spinal cord - paresthesia (sensation of goosebumps, tingling). Cancer alertness should also arise when isolated pleurisy or pericarditis is detected.

Late symptoms include: temperature without visible inflammation and infection, cachexia, exhaustion. Bone pain is indicative of metastases.

Harbingers of mediastinal cancer are so diverse that not every doctor can suspect its development. In this case, you can’t just palpate the bump or see the ulcer, so instrumental examination methods remain the main methods of diagnosis.

Causes of mediastinal cancer

The causes of mediastinal cancer are varied, it is difficult to determine what triggers the oncological process. Psychosomatics - one of the branches of medicine - believes that oncology is formed due to a change in the psycho-emotional state of a person.

Genetics blames heredity when the gene that provokes the formation of atypia is inherited. Predisposition may occur during the formation of the embryo due to a violation of fetal embryogenesis.

There is also a viral theory, according to which the pathogen (for example, the papillomavirus, AIDS or herpes) causes the appearance of gene mutations. However, mediastinal cancer is not contagious to others, it is impossible to get it by airborne droplets or in any other way.

Doctors identify factors that cause oncological degeneration, the main of which are:

• . age - the body's immunological defense gradually decreases;
• . carcinogens coming from food or due to environmental pollution;
• . radiation and exposure;
• . pathology of pregnancy;
• . chronic diseases.

Stage characterizes the degree of spread of mediastinal cancer:

• . zero, or in situ (0) - at an early stage, the pathology is practically not detected;
• . the first (1) is an encapsulated tumor without invasion into the mediastinal tissue;
• . the second (2) - there is an infiltration of fatty tissue;
• . the third (3) - germination of several organs of the mediastinum and lymph nodes;
• . the fourth and last (4) are distant organs affected by metastases.

Photographs and images of computed and magnetic resonance imaging, which are attached to the conclusion of a diagnostician, will help determine the degree.

If mediastinal cancer is suspected, to check it, identify the neoplasm and make a diagnosis, use:

• . survey, acquaintance with the history of the disease;
• . examination (finger-finger percussion, palpation);
• . test for tumor markers;
• . Ultrasound - shows other foci;
• . x-ray examination and fluorography (the main method of diagnosis);
• . endoscopic examinations (bronchoscopy, esophagoscopy, thoracoscopy);
• . PET-CT scan to determine distant metastasis;
• . computed or magnetic resonance imaging to obtain layered photographs of cancer formation.

Treatment of mediastinal cancer

Mediastinal cancer is curable if patients turn to a specialist in time. Thoracic surgery offers an effective anti-cancer remedy that will help defeat and get rid of cancer. The surgeon's actions are aimed at the complete removal of the involved structures under general anesthesia. Operable mediastinal cancer and all affected tissues are removed by thoracotomy, after which radiation and chemotherapy are prescribed. The goal is to stop the growth of the tumor, slow down the spread. Radiation and chemotherapy are also used if there are contraindications to surgery. Symptomatic therapy can help alleviate the condition at all stages - the sick person takes strong painkillers, cardiovascular drugs.

Sometimes clinical remission does not last long. When the disease occurs repeatedly (relapses), the patient's life expectancy is reduced and treatment tactics change. If left untreated, mediastinal cancer is fatal. Advanced mediastinal cancer and the decay of a cancerous tumor also affect the time allotted to the patient. The survival rate is 35%, it is affected by the speed, time of the course and the dynamics of the process. Recovery is possible with the timely detection of a tumor, which often happens when contacting a medical institution for other diseases with similar symptoms, or at preventive examinations.

Prevention of mediastinal cancer

Since the etiology of mediastinal cancer varies and there is no way to completely eliminate the damaging factor, in order to prevent it, it is recommended to perform general recommendations that reduce the chance of getting sick and to some extent protect against cancer:

• . active lifestyle;
• . lack of bad habits (smoking, alcohol);
• . normal sleep;
• . daily regime;
• . healthy food.

Stress, overwork, strong physical exertion should be avoided, preventive examinations and fluorography, which can show education, should be done on time. Only timely medical care will help to avoid death.

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The mediastinum is the area located between the pleural sacs. Bounded laterally by the mediastinal pleura, it extends from the superior thoracic inlet to the diaphragm and from the sternum to the spine. The mediastinum is potentially mobile and is normally kept in the middle position due to the balance of pressure in both pleural cavities. In rare cases, holes in the mediastinal pleura cause communication between the pleural sacs. In infants and young children, the mediastinum is extremely mobile, later it becomes more rigid, so that unilateral changes in pressure in the pleural cavity have a correspondingly less effect on it.

Fig.34. Divisions of the mediastinum.

Anatomists divide the mediastinum into 4 sections (Fig. 34). The lower border of the superior mediastinum is a plane drawn through the manubrium of the sternum and the IV thoracic vertebra. This arbitrary border runs below the aortic arch just above the tracheal bifurcation. The anatomical boundaries of the other compartments are shown in Table 18. Lesions with increasing volume in the mediastinum can shift the anatomical boundaries, so that the lesion, which usually occupies its own zone, can spread to others. Changes in the small congested upper mediastinum are especially prone to overstep arbitrary boundaries. However, in the norm, some formations extend to more than one department, for example, the thymus gland, which extends from the neck through the superior mediastinum to the anterior, the aorta and esophagus, located in both the superior and posterior mediastinum. The anatomical division of the mediastinum is of little clinical significance, but localization of lesions in the mediastinum provides valuable information in establishing the diagnosis (Table 19 and Figure 35). However, the diagnosis can rarely be established and even more rarely benign and malignant lesions can be distinguished before accurate histological data are obtained. In 1/5 of cases, tumors or cysts of the mediastinum may undergo malignant transformation.

Fig.35. Localization of tumors and cysts of the mediastinum on the lateral radiograph.