ODESSA NATIONAL MEDICAL UNIVERSITY

Department of surgery №3

RECOMMENDATIONS to practical classes for surgery course for medical faculty students of V-th year on the theme:

" Diseases of mediastinum".

Discussed and ratified onto the

methodical conference of the Department

"28.08.2020 ",

Minutes №1

Head of the Department

professor __________O. I. Tkachenko

Odessa – 2020

1. Introduction

Progressive growth of amount of found out the tumours of mediastinum, which was observed

during the last years, makes the question of diagnostics of these diseases in the row of primary problems of modern clinical oncology. It will be to establish, that, without regard to the enormous

amount of examination, devoted this problem, the objective estimation of reality does not allow to count the nowaday state of diagnostics of tumours of mediastinum satisfactory.

Difficulties of diagnostics and especially differential diagnostics of tumours of mediastinum is

explained also absence at dividing majorities from them typical clinical signs. Malignant tumours flow unfortunately without symptoms, and quite often first appear at a prophylactic roentgenologic

examination. Patients in most cases speak to the doctors of general medicine that is why knowledge of these

pathologies, basic symptoms of disease, tactic of patients conducting is necessary for all doctors of

general medicine.

3. Purpose of the lesson:

3.1. General: to familiarize with modern determination of diagnostics and treatment of patients with the tumours of mediastinum.

3.2. Educate:

1. To familiarize with contribution of domestic scientists in the study of problem of

diagnostics and treatment of patients with the tumours of mediastinum. 2. Able to explain to the patients the necessity of prophylactic roentgenologic examination

of thoracic organs and timely address to the specialized hospital.

3.3. Concrete:

- to know:

1. Basic clinical symptoms of tumours of lungs. 2. Basic clinical symptoms of tumours of mediastinum. 3. Symptoms of “small signs”.

4. Classification of tumours of mediastinum. 3.4. On the basis of theoretical knowledges from a theme to lay hands on methods (able):

1. To execute the complete examination of patient, collection of anamnesis. 2. To appoint necessary laboratory and instrumental examination. 3. To read roentgenologic pictures.

4. Material of pre-auditory individual training

(interdisciplinary integration)

№ Disciplines To know To be able

1. Previous disciplines

1 Anatomy and Physiology Anatomical-physiological features of lungs and organs of mediastinum

2 General Surgery Methods of surgical patient’s examination

1. To conduct questioning of patient 2. To appoint physical examination

of patient 3. To estimate laboratory and

instrumental investigations’ results

4. To make plan of treatment

3 Facultative Surgery Basic principles of patients with lungs and mediastinum tumours treatment

To make tactic of treatment, plan and amount of surgical intervention

2. Next disciplines

4 Hospital Surgery Etiology, pathogenesis, classification, clinic, treatment. Prophylaxis and complications of lungs and mediastinum tumours

1. To conduct a differential diagnosis swelled lungs and mediastinum.

2. To define the plan of treatment a patient with the tumours of lungs or mediastinum

3. To give a necessary help.

3. Inter-subject integration 1. Acute pneumonia

2. Exudative pleurisy 3.Myocardium infarction

Intercommunication between the tumours of lungs, mediastinum and by the adopted nosologies.

1. To diagnose at patient with tumours of lungs and mediastinum another diseases of abdominal cavity

2. To correct treatment of patients with tumours of lungs and mediastinum with dependences on certain diseases.

5. Content of the theme

MEDIASTINUM

Mediastinal abnormalities may manifest as an asymptomatic mass identified on screening

CXR or with significant symptoms, including hypoxia, facial swelling, and acute respiratory distress. Symptoms are related to the involvement of the specific mediastinal structures. Thoracic imaging with contrast-enhanced CT and MRI play critical role in the characterization of mediastinal masses.

Cytology lymphomas. In children, the most common pathologies are neurogenic tumors, germ cell tumors, primary cysts, and lymphomas.

Pericardial cysts and thymomas are uncommon in children. Malignant mediastinal neoplasms account for 25% to 50% of mediastinal masses in adults. Lymphomas, thymomas, germ cell tumors, primary carcinomas, and neurogenic tumors are the most common. Many mediastinal lesions occur in

characteristic sites within the mediastinum (Fig. 58.38). They may cause specific symptoms due to compression or invasion of adjacent structures. Approximately half of all mediastinal masses are

located in the anterosuperior mediastinum, with the remainder divided between the posterior and middle mediastinum.

Classification of tumours

Thymoma

Thymic carcinoma

Lymphoma Hodgkin disease Lymphoblastic lymphoma

Large cell lymphoma Germ cell tumors

Teratodermoid (benign/malignant) Seminoma Nonseminoma

• Embryonal • Choriocarcinoma

• Endodermal Primary carcinomas

Mesenchymal tumors

• Fibroma/fibrosarcoma • Lipoma/liposarcoma

• Leiomyoma/leiomyosarcoma • Rhabdosarcoma

• Xanthogranuloma • Myxoma • Mesothelioma

• Hemangioma • Hemangioendothelioma

• Hemangiopericytoma • Lymphangioma • Lymphangiomyoma

• Lymphangiopericytoma Endocrine tumors

• Intrathoracic thyroid • Parathyroid adenoma/carcinoma • Carcinoid

Cysts

Bronchogenic

Pericardial Enteric Thymic

Thoracic duct Nonspecific

Giant lymph node hyperplasia Castleman disease Chondroma

Extramedullary hematopoiesis Neurogenic tumors

Neurofibroma Neurilemoma Paraganglioma

Ganglioneuroma Neuroblastoma

Chemodectoma Neurosarcoma

Anterosuperior Compartment

The anterosuperior compartment of the mediastinum borders the undersurface of the sternum

ventrally, the pericardium dorsally, and the visceral pleura laterally (at the apposition of the pleura and pericardium). Among adults older than 40 years old, thymomas are the most frequently occurring neoplasm of the anterior mediastinum, and the second most common pathology is retrosternal goiter.

Other pathologies are lymphomas, seminomas, nonseminoma germ cell tumors, and teratomas. Between the ages of 10 and 40 years old, lymphomas and teratomas in women and lymphomas,

seminomas, nonseminoma germ cell tumors, and teratomas in men are the most frequently occurring neoplasms of the anterior mediastinum. In children younger than 10 years of age, lymphomas and teratomas are the most frequently occurring neoplasms of the anterior mediastinum. In this age group,

benign thymic pathologies, such as thymic cysts or hyperplasia, are also encountered. Additional pathologies of the anterior mediastinum include carcinoid tumors, which may be found within the

thymus, and primary carcinomas of the mediastinum, which are often unresectable and respond poorly to treatment (Fig. 58.39).

FIG. 58.38 Lateral chest radiograph demonstrating the mediastinum divided into three anatomic subdivisions

FIG. 58.39 Thyroid carcinoma w ithin the mediastinum. The tumor w as resected via median sternotomy. No invasion w as identif ied. A complete resection w as accomplished

Middle Compartment

The middle (or visceral) compartment extends from (and contains) the structures of the

thoracic inlet (superiorly), the pericardium anteriorly, to the anterior surface of the vertebrae posteriorly. Lymphomas can occur in the middle mediastinum. Tumors of the heart and great vessels as well as tumors of the trachea, mainstem bronchi, and esophagus may be considered tumors of the

middle compartment. Benign diseases, such as pericardial cysts and bronchogenic cysts, also occur here. Vascular masses and enlargement may represent aortic pathologies such as aortic aneurism,

abscess, or dissection.

Posterior or Paravertebral Sulci Compartment

The posterior compartment is bounded by the middle compartment anteriorly and the costophrenic angle laterally. Neurogenic tumors are usually the most common primary tumors of the

mediastinum, and approximately 25% of these tumors are malignant. These tumors are located within the paravertebral sulcus and may erode the adjacent vertebra

or rib. Schwannomas and neurilemomas are the most common neurogenic tumors. Neurofibromas arise

from the nerve sheath and fibers and occur in middle-aged patients. In children, ganglioneuroma is the most common neurogenic tumor. Posterior mediastinal tumors frequently attain a large size before

presentation of symptoms. Surgical resection of these neurogenic tumors is usually the procedure of choice.

Embryologic development of the neural crest cells forms the basis of neuroendocrine tumors

in the mediastinum. Of pheochromocytomas, 1% occurs within the mediastinum. Chemodectomas or paragangliomas may arise from chemoreceptor tissues around the aorta and great vessels, including the

carotid. Symptoms may result from catecholamine production and are alleviated by surgical resection.

Clinical Manifestations and Diagnosis

Approximately one third of adult patients may develop symptoms from a mediastinal mass. Symptoms include chest pain, dyspnea, and cough. The symptoms may vary widely and relate to size

(fatigue, weight loss), location, extent of compression or invasion of mediastinal structures (superior vena cava syndrome), and production of hormones, markers, or other biochemical materials (e.g., myasthenia gravis, fatigue, night sweats). Larger mediastinal tumors are more likely to produce

symptoms. Benign lesions are more often asymptomatic. Superior vena cava syndrome (obstruction of the superior vena cava with head and neck and upper extremity swelling), cough, hoarseness (from

involvement of the recurrent laryngeal nerve), dyspnea from tumor volume or phrenic nerve paralysis, and dysphagia occur with compression or invasion of mediastinal structures. Other manifestations

include Horner syndrome and Pancoast syndrome. Infections within the mediastinum are devastating. Because of the extensive thin areolar planes between major structures, infections within a limited portion of the mediastinum may spread vertically or horizontally to create an extensive infection.

Synergistic aerobic and anaerobic infections from the perforated esophagus are particularly life-threatening. Treatment consists of surgical drainage and antibiotics.

Specific clinical syndromes may occur as a result of mediastinal tumors. Physical examination may reveal swelling of the head, neck, or upper extremities. Dyspnea may result from compression of the trachea, bronchus, or a portion of the lung parenchyma. Recurrent respiratory

symptoms may occur for some time until a CXR is obtained and the abnormality is identified. Postobstructive pneumonitis or infection of benign pericardial or enteric duplication cysts may produce

fever or sepsis. Myasthenia gravis may result from thymomas. In addition, thymomas may result in autoimmune problems, such as hypogammaglobulinemia, red cell aplasia, and smooth muscle degeneration. Mediastinal Hodgkin disease may produce an intermittent fever. Patients with

hypertension from pheochromo- cytoma, thyrotoxicosis from goiter, hypercalcemia from ectopic mediastinal parathyroid adenoma or carcinoma, or hypogammaglobulinemia should be evaluated

carefully; mediastinal findings may affect subsequent therapeutic recommendations.

Evaluation and Diagnostic Imaging

Diagnostic imaging typically includes a plain CXR taken in two planes (posteroanterior and left lateral), which provides basic information about the location of the mass within the mediastinum.

Given the known propensity of specific lesions to occur in the anterior, visceral (middle), or paravertebral (posterior) sulcus based on the anatomy and embryologic development of cervicothoracic organs, a differential diagnosis may be obtained.

CT scan of the chest has replaced plain CXRs as the diagnostic procedure of choice for mediastinal masses. MRI is used if invasion to specific anatomic structures/location in the mediastinum

is in doubt. To illustrate, an anterior mediastinal mass, such as a thymoma, can be evaluated for the extent of compression or possible invasion into the pulmonary artery, innominate vein, or superior vena cava. Similarly, posterior mediastinal masses can be evaluated

by MRI for the extent of invasion into the brachial plexus, great vessels, vertebral body, neural foramina, and spinal column. Echocardiography may identify pericardial and cardiac involvement.

When malignancy is suspected PET-CT is used to evaluate the extent of systemic disease. Additional scans may be used in specific scenarios (technetium scan for ectopic thyroid tissue or a substernal goiter and 131-I metaiodo- benzylguanidine for mediastinal pheochromocytoma). If the

CXR shows an elevated diaphragm, fluoroscopy or ultrasonography is used to evaluate paradoxical motion of the diaphragm indicative of phrenic nerve paralysis.

Mediastinal tumors may secrete specific hormones or biologic markers. Parathyroid adenomas or functioning parathyroid carcinomas may secrete parathormone. Pheochromocytomas may secrete various catecholamines (in serum and urine), which may cause hypertension. Carcinomas may

secrete carcinoembryonic antigen. Nonseminomatous germ cell neoplasms may secrete α-fetoprotein (AFP) or β-human

chorionic gonadotropin (β-HCG). Lymphomas may be associated with elevated levels of LDH and alkaline phosphatase.

Thymomas may be associated with production of antiacetylcholine receptor (AChR)

antibodies. Skin tests for tuberculosis, histoplasmosis, and coccidioidomycosis may also yield positive results. Other diagnostic tests for mediastinal tuberculosis include sputum cytology, CXR, and urine

cytology.

Histologic Diagnosis

Radiographic diagnosis may be sufficient for the design of a treatment plan for mediastinal

cysts and for other solid lesions that are clearly resectable (early stage thymoma). However, tissue for definitive diagnosis is required for the workup of more complex solid masses. Fine-needle aspiration or

needle biopsy with CT guidance of a mediastinal mass may provide sufficient tissue for diagnosis for thymic carcinoma or other defined neoplasms. For lymphomas in particular, as well as thymomas and neural tumors, larger amounts of tissue may be required for cellular analysis. In these patients, core

needle biopsy, mediastinoscopy, or intrathoracic biopsy (via thoracoscopy or open thoracotomy) may be considered. For recurrent lymphomas, after chemotherapy, open techniques for incisional biopsy are

often required. When upfront resection is considered for diagnosis and treatment, median sternotomy

provides a direct visual approach to the anterior and middle mediastinum. Thoracotomy provides direct

visual approach to the posterior mediastinum. VATS techniques and robotic techniques of resection are increasingly used for treatment of noninvasive tumors. More extensive approaches include the

transverse sternotomy or “clam-shell” incision. Anesthetic considerations should include avoidance of airway obstruction, awake intubation, and use of muscle paralytics in patients with myasthenia gravis.

PRIMARY MEDIASTINAL CYSTS

Primary cysts of the mediastinum account for approximately 20% of mediastinal masses in

most collected series. Cysts are characterized from the organ of origin and may be bronchogenic, pericardial, enteric, or thymic, or may be of an unspecified nature.

More than 75% of cases are asymptomatic, and these tumors rarely cause morbidity;

however, with proximity to vital structures within the mediastinum and increasing size, the cyst may cause significant problems. Benign cysts may be resected with minimally invasive techniques.

Bronchogenic cysts account for most primary cysts of the mediastinum (see Fig. 58.9).

FIG. 58.9 Tw o chest x-rays (A) and a computed tomography scan (B) of the chest of a patient w ith a bronchogenic cyst

(arrow).

They originate as sequestrations from the ventral foregut, the antecedent of the tracheobronchial tree, and can be situated within the lung parenchyma or the mediastinum.

Bronchogenic cysts are usually located proximal to the trachea or bronchi and may be just posterior to the carina. A connection to the bronchus rarely exists; however, when it occurs, these cysts may become infected. Diagnostic imaging may reveal an air-fluid level within the mediastinum. Two

thirds of bronchogenic cysts are asymptomatic. In infants, cysts cause severe respiratory compromise by compressing the trachea or the bronchus. Resection is recommended.

Pericardial cysts are second in frequency to bronchogenic cysts and occur in the cardiophrenic angle mostly on the right side (70%). These cysts may or may not communicate with the pericardium. Typically, clear fluid is encountered. The characteristics of pericardial cysts include

location in the cardiophrenic angle, characteristic appearance, smooth borders, and attenuation approximating water for the cyst fluid. Needle aspiration and routine surveillance may be all that is

needed. Resection may be used for diagnosis and to exclude malignant tumors. Enteric cysts or duplication cysts arise from the primitive foregut, which develops into the

upper division of the gastrointestinal tract. These cysts are usually attached to the esophagus.

Symptoms occur as size increases with compression of the esophagus and dysphagia. Neuroenteric cysts are associated with anomalies of the vertebral column. Excision is recommended.

PRIMARY MEDIASTINAL NEOPLASMS

Thymoma

Thymomas are the most common neoplasm of the anterosuperior compartment of the

mediastinum. They are considered as malignant tumors with varying degrees of aggressiveness. The major histologic subtypes are A, AB, and B1–B3 thymomas, with type A being the most indolent subtype and type B3 being the most aggressive subtype.

Thymic carcinomas are more aggressive than thymomas and are separately classified. Thymoma peak incidence is in the third through fifth decades, but they may occur throughout

adulthood. Thymoma is rare in the first two decades of life. A thymoma may appear on a radiograph as a small, well-circumscribed mass or as a bulky, lobulated mass confluent with adjacent mediastinal structures (Fig. 58.40).

FIG. 58.40 (A) Computed tomography (CT) scan of the chest in a patient with myasthenia

gravis and thymoma.

The thymoma is small with a plane of separation between the tumor and the pericardium. (B) Chest CT scan in a patient with a larger mediastinal mass. The location, character, and size are noted. Transthoracic core needle biopsy was performed. Germ cell tumor markers were normal. Pathology

demonstrated thymoma. A 6.5-cm thymoma was subsequently resected. There was no invasion of the pericardium. A complete resection(R0) was accomplished.

Symptoms at presentation are related to local mass effects causing chest pain, dyspnea, hemoptysis, cough, and superior vena cava syndrome or systemic syndromes caused by immunologic mechanisms. The most common syndrome is myasthenia gravis (in up to 50% of cases); other

syndromes include pure red blood cell aplasia, hypogammaglobulinemia, and thymoma-associated multiorgan autoimmunity. Staging of thymomas and thymic carcinomas is based on the extent of the primary tumor and the presence of invasion into adjacent structures and/or dissemination. Until

recently, thymomas were staged according to the modified Masaoka-Koga system; however, a formal TNM-based staging system for thymic tumors has recently been issued by the AJCC as part of its

eighth edition cancer staging manual (Table 58.5).

From a surgical perspective, thymomas may be viewed as those that can be completely resected, those that are potentially resectable, and those that cannot be completely resected. Patients presenting with small fully encapsulated thymomas should undergo surgery. Patients that present with

invasive but potentially resectable tumors are managed by a multidisciplinary team of expert. Neoadjuvant and adjuvant chemotherapy, radiation, and immunotherapy are applied in conjunction

with extensive surgery to achieve complete or at least macroscopic complete resection of the tumor with the aim of preventing or deferring disease recurrence. Resection and reconstruction of involved mediastinal structures, including the superior vena cava and innominate vein, as well as resection of

droplet metastatic lesions, may in selected patient achieve significant prolongation of survival. As a rule of thumb, survival is dictated by the histologic subtype, by disease stage, and by the extent of

resection. For patients with myasthenia gravis and thymoma, surgery is advocated as soon as the

patient’s degree of weakness is sufficiently controlled to permit surgery. Attentive perioperative

management in these patients is crucial to prevent complications. Anticholinesterase inhibitors, plasmapheresis, and/or intravenous immunoglobulin are used pre- and postoperatively to control

generalized weakness. Intensive pulmonary toilet, early extubation if possible, chest physiotherapy, and avoidance of paralyzing agents and narcotics are central in assuring proper recovery from surgery. During surgery, complete resection of the entire thymus and all accessible mediastinal fatty areolar

tissue is performed to ensure removal of all ectopic thymic tissue and to reduce the incidence of tumor recurrences. Protection and preservation of the phrenic nerves is an important integral component of

thymectomy. Improvement in myasthenia gravis symptoms and reduction in the dosages of drugs required to control the disease is anticipated to a certain extent in the months following surgery.

Germ Cell Tumors

Germ cell tumors arise from primordial germ cells that fail to complete the migration from the urogenital ridge and rest in the mediastinum. Treatment depends on histology. The antero- superior mediastinum is the most common extragonadal primary site of these tumors. Although these lesions are

identical histologically to germ cell tumors originating in the gonads, they are not considered metastatic from primary gonadal tumors. The current recommendations for evaluating the testes of a patient with

mediastinal germ cell tumor are careful physical examination and ultrasonography of the testes. Biopsy is reserved for positive findings. Blind biopsy or orchiectomy is contraindicated.

Teratomas

Teratomas are the most common mediastinal germ cell neoplasms and are located most

commonly in the anterosuperior mediastinum. They are composed of multiple tissue elements that are derived from the three primitive embryonic layers foreign to the area in which they occur. The peak incidence is in the second and third decades of life. There is no gender predisposition.

Radiographic evidence of normal tissue (e.g., well-formed teeth or globular calcifications, a fatty mass) in an abnormal location can be considered specific. The teratodermoid (dermoid) cyst is

the simplest form of a teratoma and is composed of derivatives of the epidermal layer, including dermal and epidermal glands, hair, and sebaceous material. Teratomas are histologically more complex. The solid component of the tumor often contains welldifferentiated elements of bone, cartilage, teeth,

muscle, connective tissue, fibrous and lymphoid tissue, nerve, thymus, mucous and salivary glands, lung, liver, or pancreas. Malignant tumors are differentiated from benign tumors by the presence of

primitive (embryonic) tissue or by the presence of malignant components. Immature teratomas contain combinations of mature epithelial and connective tissues with

immature areas of mesenchymal and neuroectodermal tissues. Teratomas with malignant components

are divided into categories based on the elements present. Diagnosis and therapy rely on surgical excision. For benign tumors of large size or with

involvement of adjacent mediastinal structures such that complete resection is impossible, partial resection has led to resolution of symptoms, frequently without relapse. For malignant teratomas,

chemotherapy, and radiation therapy, combined with surgical excision, are individualized for the type of malignant components contained in the tumors. The overall prognosis is poor for malignant teratomas.

Malignant Nonteratomatous Germ Cell Tumors

Malignant germ cell tumors occur predominantly in the anterosuperior mediastinum with a marked male decades of life. Most patients have symptoms of chest pain, cough, dyspnea, and hemoptysis; the superior vena cava syndrome occurs commonly. A large anterior mediastinal mass is

identified on diagnostic imaging.There is evidence of intrathoracic spread of disease. CT and MRI are helpful to define the extent of the disease and involvement of mediastinal structures. Serologic

measurements of AFP and β-HCG are useful for differentiating seminomas from nonseminomatous tumors, assessing response to therapy, and diagnosing relapse or failure of therapy. Seminomas rarely produce β-HCG and never produce AFP; in contrast, more than 90% of nonseminomatous tumors

secrete one or both of these hormones. This differentiation is important, as seminomas are radiosensitive, and nonseminomatous tumors are relatively radioinsensitive.

Seminomas

Seminomas constitute 50% of malignant germ cell tumors. Seminomas usually remain

intrathoracic. Symptoms are related to the mechanical effects of the tumor on adjacent mediastinal and pulmonary structures. The superior vena cava syndrome occurs in 10% to 20% of patients. These

tumors are sensitive to irradiation and chemotherapy. Therapy is determined by the stage of the disease. Cytoreductive resection before chemotherapy or radiation therapy is unnecessary. Treatment consists of systemic and local therapy—chemotherapy with salvage surgery or combined chemoradiotherapy.

Radiation therapy may be considered for early-stage disease but is not recommended for regional disease.

Platinum-based chemotherapy is common. Occasionally, excision is possible without injury to vital structures and can be recommended. When complete resection is possible, the use of adjuvant therapy is unnecessary. When excision is impossible, a biopsy sample of sufficient size to

establish the diagnosis is obtained.

Nonseminomatous Tumors

Malignant nonseminomatous germ cell tumors include choriocarcinomas, embryonal cell carcinomas, immature teratomas, teratomas with malignant components, and endodermal cell (yolk

sac) tumors and occur mostly in men in their third or fourth decades. Diagnostic imaging reveals a large anterior mediastinal mass with frequent extension to the

lung, chest wall, and mediastinal structures. Nonseminomatous germ cell neoplasms are more aggressive tumors and more frequently disseminated at the time of diagnosis, they are rarely radiosensitive, and more than 90% produce either β-HCG or AFP. All patients with choriocarcinoma

and some patients with embryonal cell tumors have elevated levels of β-HCG. AFP is most commonly elevated in patients with embryonal cell carcinomas and yolk sac tumors. Mediastinal

nonseminomatous germ cell tumors, but not testicular germ cell tumors, are associated with the development of rare hematologic malignancies, such as acute megakaryocytic leukemia, systemic mast cell disease, and malignant histiocytosis, as well as other hematologic abnormalities, including

myelodysplastic syndrome and idiopathic thrombocytopenia refractory to treatment. Treatment of these nonseminomatous tumors currently is with cisplatin and etoposide-

based regimens. Advanced disease, invasion into thoracic structures, and metastasis preclude surgical resection. Serum markers, AFP or β-HCG, are followed to assess response to systemic treatment. If a complete serologic and radiologic response is achieved, patients are closely observed. If the disease

progresses during therapy, salvage chemotherapy is initiated. Operative intervention may be required to establish a histologic diagnosis in patients

without elevations in serum AFP or β-HCG or for salvage resection after tissue or serologic response to therapy.

The pathology of the resected postchemotherapy specimen appears to be the most significant predictor of survival. The presence of residual disease after chemotherapy portends a poor prognosis and the need for additional chemotherapy. When tumor necrosis or a benign teratoma is

found during surgical exploration after chemotherapy, an excellent or intermediate prognosis is conferred, respectively.

Neurogenic Tumors

Neurogenic tumors are usually located in the posterior mediastinum and originate from

the sympathetic ganglia (ganglioma, ganglioneuroblastoma, and neuroblastoma), the intercostal nerves (neurofibroma, neurilemoma, and neurosarcoma), and the paragangliacells (paraganglioma). Although

the peak incidence occurs in adults, neurogenic tumors make up a proportionally greater percentage of mediastinal masses in children. Although most neurogenic tumors in adults are benign, a greater percentage of neurogenic tumors are malignant in children.

The most common neurogenic tumor is neurilemoma or schwannoma, which originates from perineural Schwann cells. They are benign, slow-growing neoplasms that frequently arise from a

spinal nerve root but can involve any thoracic nerve. These tumors are well circumscribed and have a defined capsule. They arise from the nerve sheath and extrinsically compress the nerve fibers. The peak incidence of these tumors is in the third through fifth decades of life; men and women are equally

affected. Many of these tumors are asymptomatic. Symptoms such as pain occur from compression or invasion of intercostal nerve, bone, and chest wall; cough and dyspnea resulting from compression of

the tracheobronchial tree; Pancoast syndrome; and Horner syndrome resulting from involvement of the brachial and the cervical sympathetic chain. Approximately 10% of neurogenic tumors have extensions into the spinal column and are termed dumbbell tumors because of their characteristic shape with

relatively large paraspinal and intraspinal portions connected by a narrow isthmus of tissue traversing the intervertebral foramen. Patients with paraspinal tumors should undergo MRI to evaluate the

presence and extent of the tumor and its relationship to the neural foramen and the intraspinal space. During resection, the intraspinal component should be removed first via a posterior laminectomy. This approach minimizes the potential for spinal column hematoma, cord ischemia, and paralysis. A

separate transthoracic approach isneeded for resection of the intrathoracic component.

Neuroblastoma

Neuroblastomas originate from the sympathetic nervous system. The most common location for a neuroblastoma is in the retroperitoneum; however, 10% to 20% occur primarily in the

mediastinum. These are highly invasive neoplasms that have frequently metastasized before diagnosis. Most of these tumors occur in children 4 years old or younger. A 24-hour urine collection to measure

catecholamines is obtained in children with a posterior mediastinal mass. Therapy is determined by the stage of the disease: stage I, surgical excision; stage II, excision and radiation therapy; stages III and IV, multimodality therapy using surgical debulking, radiation therapy, and multiagent chemotherapy

and a second-look exploration to resect residual disease when necessary. The usual chemotherapeutic agents are cisplatin, vincristine, doxorubicin, cyclophosphamide, and etoposide.

Ganglion Tumors

Ganglioneuroblastomas are composed of mature and immature ganglion cells. Treatment

of ganglioneuroblastoma ranges from surgical excision alone to various chemotherapeutic strategies depending on histologic characteristics, age at diagnosis, and stage of disease. Ganglioneuromas are

benign tumors that originate from the sympathetic chain and are composed of ganglion cells and nerve fibers. These tumors typically manifest at an early age and are the most common neurogenic tumors occurring during childhood.

The usual location is the paravertebral region. These tumors are well encapsulated and, when cross-sectioned, frequently exhibit areas of cystic degeneration. Surgical excision provides cure.

Paraganglioma (Pheochromocytoma)

Mediastinal paragangliomas are rare tumors, representing less than 1% of all mediastinal tumors and less than 2% of all pheochromocytomas. Although most are found in the paravertebral sulcus, an increasing number occur in the branchial arch structures, coronary and aortopulmonary

paraganglia, atria, and islands of tissue in the pericardium. Although adrenal pheochromocytomas often produce both epinephrine and norepinephrine, extra-adrenal paragangliomas rarely secrete epinephrine.

Multiple paragangliomas occur in 10% of patients. These tumors are more common in patients with multiple endocrine neoplasia syndromes, a family history of disease, and Carney syndrome (pulmonary chondroma, gastric leiomyosarcoma, and functioning extra-adrenal paraganglioma). In patients who

have had excision of an adrenal pheochromocytoma and continue to have symptoms, a search for an extra-adrenal lesion is undertaken with careful attention to the mediastinum. Tumor localization has

improved through the use of CT and iodine-131 metaiodobenzylguanidine scintigraphy, particularly when the tumors are hormonally active. When appropriate, surgical resection is the optimal therapy. In patients with tumors involving the middle mediastinum, cardiopulmonary bypass may be necessary to

enable resection. Preoperative embolization to reduce perioperative bleeding may be considered. Although half of tumors appear malignant morphologically, metastatic disease rarely develops.

Lymphomas

Although the mediastinum is frequently involved in patients with lymphoma at some

time during the course of their disease, it is infrequently the sole site of disease at the time of presentation. Hodgkin and non-Hodgkin lymphoma are distinct clinical entities with overlapping

features. Patients usually have symptoms, with chest pain, cough, dyspnea, hoarseness, and superior vena cava syndrome being the most common clinical manifestations.

Nonspecific systemic symptoms of fever and chills, weight loss, and anorexia are

frequently noted. Surgical excision of all disease is rarely possible; the surgeon’s primary role is to provide sufficient tissue for diagnosis and to assist in pathologic staging. A needle biopsy is often

unsuccessful because larger tissue samples are needed to make a histologic diagnosis, particularly with nodular sclerosing lesions. Thoracoscopy, mediastinoscopy, or mediastinotomy and, rarely, thoracotomy or median sternotomy may be necessary to obtain sufficient tissue.

Patients with non-Hodgkin lymphoma usually have symptoms because of involvement of adjacent mediastinal structures. Superior vena cava syndrome is relatively common. Lymphoblastic

lymphoma occurs predominantly in children, adolescents, and young adults and represents 60% of cases of mediastinal non-Hodgkin lymphoma.

After treatment of lymphomas, residual radiographic abnormalities within the

mediastinum are commonly noted (64% to 88%). CT cannot differentiate fibrosis or necrosis from residual tumor. FDG-PET has shown promise as a noninvasive way to detect active mediastinal disease

and predict relapse in patients with lymphoma, but tissue confirmation is required. Needle biopsy does not provide significant diagnostic material. Transthoracic incisional biopsy under general anesthesia is often needed given the significant fibrosis that remains after therapy.

Endocrine Tumors

Thyroid Tumors

Although substernal extension of a cervical goiter is common, totally intrathoracic thyroid tumors are rare and make up only 1% of all mediastinal masses in collected series. These tumors arise

from heterotopic thyroid tissue, which occurs most commonly in the anterosuperior mediastinum but may also occur in the middle mediastinum between the trachea and the esophagus as well as in the

posterior mediastinum. Although there may be a demonstrable connection with the cervical gland (usually a fibrous connective tissue band), a true intrathoracic thyroid gland derives its blood supply from thoracic vessels. Substernal extensions of a cervical goiter can usually be excised using a cervical

approach.

Parathyroid Tumors

Although parathyroid glands may occur in the mediastinum in 10% of patients, they are

usually accessible through the cervical incision. Most often, these adenomas are found in the anterosuperior mediastinum (80%) embedded in or near the superior pole of the thymus. This anatomic relationship is the result of the common embryogenesis of the inferior parathyroid glands from the third

branchial cleft. The superior parathyroid glands and the lateral lobes of the thyroid gland are derived from the fourth branchial pouch. Because they migrate with the lateral lobes of the thyroid gland to a

paraesophageal position, parathyroid adenomas can also be found in the posterior mediastinum. Most frequently, the mediastinal parathyroid adenoma may be excised after a negative

exploration of the cervical region through the existing cervical incision. Usually the vascular supply

extends from cervical blood vessels. In patients with persistent hyperparathyroidism after cervical exploration, if localization studies show residual parathyroid in the mediastinum, mediastinal

exploration using a median sternotomy or thoracoscopy is indicated. Parathyroid carcinomas have been reported and are usually hormonally active. Patients

differ in clinical presentation in that they often have higher serum calcium levels and manifest more

severe symptoms of hyperparathyroidism. When possible, resection is the optimal therapy.

Neuroendocrine Tumors

Mediastinal neuroendocrine tumors and carcinoid tumors, arise from cells of Kulchitsky located in the thymus and commonly occur in men in their 40s and 50s. They are usually located in the

anterosuperior mediastinum. These tumors are aggressive and 20% have metastatic spread to mediastinal and cervical lymph nodes, liver, bone, skin, and lungs. More than 50% of thymic

neuroendocrine tumors are hormonally active, often associated with Cushing syndrome because of production of adrenocorticotropic hormone, less frequently associated with multiple endocrine neoplasia syndromes, and only rarely associated with carcinoid syndrome (0.6%). If possible, resection

is recommended; however, local invasion and metastasis often preclude complete excision. Adjuvant therapy is controversial, but irradiation should probably be added, particularly in patients with capsular

invasion.

6. Materials of the methodical providing of lesson.

Case scenarios

1. A 42-year-old man has been admitted with frank subcutaneous emphysema in the upper half of the

trunk, breathlessness and tachycardia in 3 hours after trauma. Pulse rate: 120/min. The X-ray didn't

reveal pneumothorax; the mediastinum is considerably expanded to both sides. What urgent management will consists of?

A. Puncture of pleural cavity B. Drainage of the anterior mediastinum C. Drainage of pleural cavity

D. Thoracoscopy E. Thoracotomy

2. In a 30-year-old man who has got a closed trauma of the thoracic cage, the general state is heavy. Cyanosis, dyspnoea, disorders of phonation and subcutaneous emphysema on the neck is being noticed. P: 100/min; BP: 80/40 mm Hg. The X-ray of the thoracic cage revealed collapse of the

right lung and a horizontal fluid level up to 5th rib and mediastinal shadow expansion. Which diagnosis can be established to the patient?

A. Massive rupture of the lung

B. Injury of the oesophagus C. Abruption of main bronchus

D. Lung crush E. Contusion of the heart

3. The basic clinical sign of exudative pericarditis is: A. Right-ventricle heart failure B. Left-ventricle heart failure

C. Intoxication D. Respiratory failure

E. Acrocyanosis

4. In a patient with post-burn stenosis of the oesophagus a fever, tachycardia, pains behind the breastbone appeared after the latest bougieunage. The X-ray reveals a horizontal fluid level in the

posterior mediastinum. The diagnosis. A. .Diverticulum of the oesophagus

B. Acute anterior mediastinitis. C. Acute posterior mediastinitis. D. Acute empyema of pleura.

E. Paraoesophageal hernia.

5. A 28-year-old woman who has been admitted to the surgical department has clinical signs of

superficial neck phlegmon. Which complications can cause the given pathology? A. Mediastinitis

B. Transition of acute strumitis in chronic

C. Asphyxia D. Thrombophlebitis

E. Mandibular periostitis

6. A 56-year-old woman was treated for 3 years for wheezing on exertion, which was diagnosed as

asthma. The chest radiograph below is obtained, which reveals a midline mass compressing the trachea.

The most likely diagnosis is

a. Lymphoma b. Neurogenic tumor c. Lung carcinoma

d. Goiter e. Pericardial cyst

Explanation

The answer is d. (Schwartz, 7/e, pp 771–780.) The boundaries of the mediastinum are the thoracic inlet, the diaphragm, the sternum, the vertebral column, and the pleura bilaterally. The mediastinum itself is divided into three portions delineated by the pericardial sac: the anterosuperior and posterosuperior regions are in front of and

behind the sac, respectively, while the middle region designates the contents of the pericardium. Mediastinal masses occur most frequently in the anterosuperior region (54%) and less often in the posterosuperior (26%) and middle (20%) regions. Cysts (either pericardial, bronchogenic, or enteric) are the most common tumors of the middle region; neurogenic tumors are the most common (40%) of the primary tumors of the posterior mediastinum. The primary neoplasms of the mediastinum in the anteroposterior region are thymomas (31%), lymphomas (23%), and germ-cell tumors (17%). More commonly, though, a mass in this area represents the substernal extension of a benign substernal goiter. Diagnosis may be made by visualization of an enhancing structure on CT; radioactive iodine scanning is useful in management because it may make the diagnosis if the mediastinal tissue is functional and will also document the presence of functioning cervical thyroid tissue to prevent removal of all functional thyroid tissue during mediastinal excision.

7.

Explanation

8. Literature for students:

1. SABISTON: TEXTBOOK OF SURGERY: THE BIOLOGICAL BASIS OF MODERN SURGICAL PRACTICE, TWENTY FIRST EDITION Copyright © 2020

2. Gozie Offiah, Arnold Hill//RCSI Handbook of Clinical Surgery for Finals. 4 th ed. 2020 3. Цигикало О. В. Clinical Anatomy and Operative Surgery=Клінічна анатомія і

оперативна хірургія.. Підручник для ВМНЗ IV р.а.: Рекомендовано МОЗ: 2020/ 528 с. 4. Березницький Я. С. (за ред.) General Surgery=Загальна хірургія. — 2-ге вид.

Підручник для ВМНЗ ІІІ—IV р.а.: Рекомендовано ДУ“Центр.метод.каб.з вищої мед.освіти МОЗ України”: 2020/ 328 с.

5. Christian de Virgilio, Areg Grigorian//Surgery: A Case Based Clinical Review. 2nd Ed.

2020 6. The Bethesda handbook of clinical oncology / editors, Jame Abraham, James L. Gulley.

Fifth Edition. Copyright © 2019 Wolters Kluwer 7. SEIDEL’S GUIDE TO PHYSICAL EXAMINATION: AN INTERPROFESSIONAL

APPROACH. Copyright © 2019 by Elsevier, Inc.

8. Hamilton Bailey's Physical Signs: Demonstrations of Physical Signs in Clinical Surgery, 19th Edition Paperback – Import, by John S.P Lumley (Author), Anil K. D'Cruz (Author), Jamal

J. Hoballah (Author), Carol E.H. Scott-Connor (Author) 25 Feb 2016 9. Schwartz's Principles Of Surgery With DVD Hardcover – 2014 by F. Charles Brunicardi

(Author), Dana K. Andersen (Author), Timothy R. Billiar (Author), David L. Dunn (Author),

John G. Hunter (Author), & 2 More

9. The task of UDRS of Research work on the topic.

1. Minimal invasive methods of treating purulent diseases of the esophagus.

2. Modern computer technologies in the diagnostics of purulent diseases of the mediastinum.

10. The theme of the next session. Oesophageal diseases and trauma of the

oesophagus

The recommendation are made by professor’s assistant Kalimnov Y.I.