What are mediastinal tumors 7-8

MEDIASTINAL TUMOR
ASHISH GEORGE MATHEW
CONTENTS
Introduction 3
Anatomy 4-6
What are mediastinal tumors 7-8
What causes mediastinal tumors 9-10
Mediastinal tumor classification 11-14
Malignant mediastinal tumors 15-19
Signs and Symptoms 20
Assessing the patient 21-22
Investigation 23-27
Differential Diagnosis 28-29
Treatment 30-34
Images 35-39
INTRODUCTION
A brief introduction അ to mediastinal അ tumors in children
we will look അ into:
anatomy അ of the mediastinum
pathophysiology of the അ mediastinum tumor
diagnostic അ criteria used in mediastinal tumor patients.
A brief account of the treatment done in mediastinal tumor is also looked upon in the following.
We will consider the kinds of mediastinal tumors found in adults and children and therefore themain presenting symptoms
This article will review regarding primary middle and posterior mediastinal neoplastic and nonneoplastic tumors that produces up about 60 minutes of mediastinal masses. lymphoma is one amongst the common mediastinal neoplasms and might involve mediastinal compartment.congenital cysts ar primarily in middle mediastinum whereas neurogenic tumors ar typical lesions of posterior mediastinum.
ANATOMY OF THE MEDIASTINUM
The mediastinum is a region found within the midline of the thorax that’s encircled by the left and right serosa sacs. it’s divided into the superior and inferior mediastinum, of that the latter is larger. The inferior mediastinum is more divided into the anterior, middle andposterior mediastinum. during this article, the borders of every section of the mediastinum and their contents are mentioned. Lastly, a pathological condition referred to as mediastinitis are mentioned.
BORDERS
The superiorഅmediastinum.beginsഅat the level ofഅthe.first rib and descends to the horizontal plane of the.thoracicvertebra T4.The.anterior inferior അmediastinum starts from.the thoracic.vertebra T4 andcontinues to the diaphragm.at the level of the thoracic vertebra T9. It extendsഅposteriorly fromഅthe body ofഅthe sternum andtransversus thoracis muscle toഅthe fibrous.pericardium.
Themiddle inferior mediastinum beginsin identical space because the anterior inferior mediastinum and finishes additionally within the same space between the T9 and T10 vertebrae. It extends posteriorly between the dimension of the fibrous pericardium.
The posterior inferior mediastinum again originates within the same place as the other 2 subdivisions but extends the deepest, to the vertebra T12. Sagittally, it runs from the posterior side of the fibrous pericardium to the spinal column.
CONTENTS
The superior mediastinum contains three visceral organs including the esophagus, thetrachea and remnants of the thymus. The nerves that run through this area are three and there are also two different nervous plexuses. The phrenic nerve, the vagus nerve and the left recurrent laryngeal nerve are the singular nerves, while the cardiac plexus branches and the pulmonary plexus branches make up the peripheral neurological plexuses. Arterial and venous constituents are comprised of the superior vena cava, the brachiocephalic veins, the thoracic duct and the aortic arch which includes the brachiocephalic artery, the common carotid artery and the left subclavian artery.
The anterior inferior mediastinum has no major contents save remnants of the thymus and some lymph nodes.
The middle inferior mediastinum contains a single nerve which is the phrenic nerve, theheart and the pericardium. The vessels present include the ascending aorta, the pulmonary trunk, the superior vena cava and the pericardiophrenic artery.
The posterior inferior mediastinum has possibly the most anatomical structures. It encompasses the esophagus, the thoracic aorta and its branches which include the posterior intercostal arteries, the bronchial arteries and the esophageal arteries. It also contains the azygos venous system, the hemiazygos and accessory hemiazygos veins, the thoracic duct, the cisterna chyli, the vagus nerve and the esophageal plexus. Lastly, the following branches of the sympathetic trunk are present: the greater splanchnic nerve, the lesser splanchnic nerve and the least splanchnic nerve.
What ar e Mediastinal Tumors (Neoplasms)?
Neoplasms ar uncontrolled growths of tissue. they will occur in nearly any space of the body. They’re additionally referred to as tumors and most frequently linked with cancer. Mediastinal tumors develop within the mediastinum. The mediastinum is that the space within the middle of the chest that lies between the sternum (breastbone) and spinal column. the area containsimportant organs together with the heart, esophagus, and trachea.
Mediastinal tumors develop in one among 3 areas of the mediastinum: the anterior (front), the middle, or the posterior (back). The position of the growth within the mediastinum usually depends on patient’s age.
Children ar more probably to develop them within the back of the mediastinum. These ar typicallybenign, or noncancerous. Adults ar more possible to develop them within the front of themediastinum. These tumors ar generally malignant, or cancerous. Affected adults ar typicallybetween the ages of thirty and fifty. As a whole, mediastinal tumors ar terribly rare.
The mediastinum is the cavity that separates the lungs from the remainder of the chest. It contains the heart, esophagus, trachea, thymus, and aorta. The mediastinum has 3 main parts: the anterior mediastinum (front), the center cavity, and therefore the posterior cavity (back).
The most common mediastinal masses area unit neurogenic tumors (20% of mediastinal tumors), sometimes found within the posterior cavity, followed by thymoma (15-20%) situated within the anterior cavity.
Masses within the anterior portion of the mediastinum will embrace thymoma, lymphoma, neoplasm, reproductive cell tumors as well as tumour, thyroid tissue, and ductless gland lesions. plenty during this space area unit additional seemingly to be malignant than those in alternative compartments.
Masses within the posterior portion of the mediastinum tend to be neurogenic in origin, and in adults tend to be of neural sheath origin including neurilemomas and neurofibromas.
Lung cancer generally spreads to the lymph nodes within the cavity.
What Causes Mediastinal Tumors?
There are a number of different types of mediastinal tumors. What causes these tumors depends on where they form in the mediastinum.
In the front of the mediastinum, tumors can be caused by:
lymphoma, including Hodgkin’s disease and non-Hodgkin’s lymphoma
thymoma and thymic cyst (a tumor of the thymus)
thyroid mass mediastinal (generally a benign growth, but it can sometimes be cancerous)
In the middle of the mediastinum, tumors can be caused by:
bronchogenic cyst (a benign growth that starts in the respiratory system)
lymphadenopathy mediastinal, or enlargement of the lymph nodes
pericardial cyst (a benign growth on the heart lining)
thyroid mass mediastinal
tracheal tumors (usually benign growths)
vascular complications, such as swelling of the aorta
In the back of the mediastinum, tumors can be caused by:
extramedullary haematopoiesis (rare growths that start in the bone marrow and are related to severe anemia)
lymphadenopathy mediastinal (enlarged lymph nodes)
neuroenteric cyst mediastinal (a rare growth involving both the nerves and the gastrointestinal system)
neurogenic neoplasm mediastinal (cancerous cells of the nerves)
Neurogenic neoplasm mediastinal is the most common cause of posterior mediastinal tumors. According to the Cleveland Clinic Foundation, about 70 percent of these are benign.
Tumors that form in the mediastinum are also known as primary tumors. Sometimes mediastinal tumors will develop because cancer from another part of the body has spread. The spread of cancer from one area of the body to another is known as metastasis. Mediastinal tumors that develop because of metastasis are known as a secondary tumor.
MEDIASTINAL TUMOR CLASSIFICATION ACCORDING TO SIDE AND SITE
Paediatric mediastinal masses are the most common chest masses in children, with the anterior mediastinum being the most common site 1.
As in adults, mediastinal masses are classified depending on anatomical sites:
anterior mediastinal masses
middle mediastinal masses
posterior mediastinal masses
Anterior mediastinal masses
Basic approach to these lesions is by chest radiograph (PA and lateral) for localisation followed by contrast-enhanced CT for characterisation:
malignant lymphoma (Hodgkin’s and non-Hodgkin’s) – most common
teratoma – common
thymus (benign enlargement) – common
thyroid (retro- or sub-sternal extension)
mesenchymal tumors
lymphangioma (cystic hygroma) – generally extends from neck into mediastinum
Middle mediastinal masses
Basic approach to these lesions is by chest radiograph (PA and lateral) for localisation, with barium swallow to identify areas of compression followed by contrast-enhanced CT for characterisation:
foregut duplication cyst (bronchogenic, enteric, and neuroenteric) – most common; bronchogenic cyst is more common
lymphadenopathy
vascular malformations
Posterior mediastinal masses
Basic approach to these lesions is by chest radiograph (PA and lateral) for localisation followed by MRI for evaluation of intraspinal extension of neurogenic tumors and distinction between vascular structures and soft tissues. Contrast-enhanced CT can be carried out when MRI is not available:
neurogenic tumor – most common
foregut duplication cyst
vascular malformations
extramedullary haematopoiesis
Malignant mediastinal tumors
Tumors within the mediastinum are best characterised by the compartment during which they arise. Malignant tumors arising within the anterior mediastinum ar most typically attributable to malignant neoplastic disease or malignant neoplastic disease followed by cell tumors. Malignant tumors of the center mediastinum ar sometimes attributable to glandular disorder from malignant neoplastic disease or malignant neoplastic disease. Middle mediastinal tumors ar typically seen in association with anterior mediastinal illness. they’re seldom seen in isolation. Tumors of the posterior mediastinum are sometimes of animal tissue origin with malignant neoplasm being most typical
Lymphoma and leukemia
Lymphoma accounts for about thirteen of all childhood cancers and is the commonest explanation for a mediastinal mass in youngsters. Sixty percent of all lymphomas during this age group are non-Hodgkin lymphomas and Hodgkin lymphomas make up the rest. though non-Hodgkin cancer is more common, concerning half the kids with non-Hodgkin lymphoma associated two-thirds of these with Hodgkin lymphoma present with an anterior mediastinal mass. Therefore, most anterior mediastinal masses in youngsters are due to Hodgkin cancer. In most cases the anterior mediastinal mass is because of infiltration of the thymus, though enlarged mediastinal nodes are usually present. The thymus and nodes are often very necrotic. Direct invasion of the serosa will result in pericardiac effusion, a well known development in Hodgkin cancer. Direct invasion of the chest wall may additionally occur. the size of the mediastinal mass and therefore the mediastinal/thoracic ratio, measured on a posterior–anterior radiograph, have implications for prognosis and risk stratification in children with Hodgkin disease. The mediastinal mass might compress and compromise the trachea and superior vena cava. when the trachea is compressed to <50% of its traditional diameter, patients mustn't be sedated or anesthetised because of the chance of airway obstruction Associated pulmonary nodules and pleural effusions occur in only about 5-hitter of patients with Hodgkin lymphoma, whereas effusions occur in 50–75% of these with lymphoblastic cancer T-cell leukemia associated lymphoblastic cancer are closely related and patients with T-cell leukemia might present with an anterior mediastinal mass and pleural effusions. the excellence between the 2 is arbitrarily supported the degree of bone marrow involvement such patients with ≥25% marrow blasts ar selected as having leukemia Malignant germ cell tumors Germ cell tumors (GCT) account for 6–18% of mediastinal masses and mediastinal primary GCTs account for 1–3% of all GCTs. concerning two hundredth of mediastinal GCTs are malignant and include seminomas and non-seminomatous tumors like teratocarcinoma, yolk sac tumour, carcinoma, choriocarcinoma, and mixed varieties. Malignant GCT is mostly a complex tumour usually containing coexistent benign parts. There are 2 age peaks for mediastinal GCTs: at about 2 years of age and adolescence. Most malignant GCTs occur in adolescent boys. Mediastinal GCTs are usually giant and cause respiratory distress as a results of compression of the tracheobronchial tree. Patients usually gift with diminished breath sounds, pain and cough Mediastinal GCTs most frequently arise inside or close to the thymus however may additionally originate within the center or pericardium and rarely in the posterior mediastinum. Benign and malignant GCTs contain calcification (33–50%), fat and cystic or death areas.. Malignant tumors tend to be massive, cause a marked mass impact and infiltrate adjacent structures. Seminomas seldom calcify and are generally homogeneous tumors. Non-seminomatous GCTs ar invasive tumors that ar inhomogeneous and contain areas of necrosis and hemorrhage[8]. Seminomas lack serological markers, whereas non-seminomatous tumors are usually associated with increased serum β-human chorionic gonadotropin or alphafetoprotein levels which will induce precocious puberty and will be related to XXY-syndrome. Seminomas need histologic diagnosing, whereas non-seminomatous tumors are often diagnosed by serum markers and clinical and imaging correlation. Neurogenic tumors Approximately ninetieth of posterior mediastinal masses in kids ar of neurogenic origin[. These include ganglion cell tumors, nerve sheath and nerve tumors, and different nerve tissue tumors like paragangliomas. Most posterior mediastinal tumors in kids are ganglion cell tumors. These tumors arise from sympathetic chain ganglia and form a spectrum of sickness starting from the foremost aggressive, neuroblastoma, to the less aggressive, ganglioneuroblastoma and benign ganglioneuroma. neuroblastoma occurs at a median age of two years, ganglioneuroblastoma at a median age of five.5 years and ganglioneuroma typically occurs after ten years of age. All 3 have similar radiologic features. On typical radiography these tumors seem as a vertically elongated mass with tapered superior and inferior margins. The lateral margin is typically smooth and convex . regarding 30 minutes contain calcification. Bone changes embrace spreading and erosion of ribs and widening of neural foramina. The clinical presentation of metastatic tumor ranges from clinically silent to symptoms related to disseminated sickness like irritability, diarrhea, weight loss, fever and bone pain.an area mass result or intraspinal tumour extension will cause metabolic process distress or wire compression. once metastatic tumor happens close to the respiratory organ apex or base of the neck, it will cause Horner syndrome (ptosis, myosis, anhydrosis). Opsoclonus-myoclonus, a syndrome characterised by fast eye movements, happens seldom. Patients with opsoclonus-myoclonus usually have tumors with favorable biological behavior however suffer from semipermanent medical specialty sequelae. Nerve sheath tumors comprises schwannomas, encapsulated tumors lacking nerve fibers, and neurofibromas, non-encapsulated tumors with nerve fibers. These tumors might arise from intercostal or sympathetic nerves. Radiologically, the tumors ar indistinguishable and frequently seem as sharply marginated, spherical and lobulated paraspinal masses. Rib erosion and splaying of ribs is additional commonly seen with nerve sheath tumors than ganglion tumors. concerning 100 percent can have intraspinal extension. On resonance imaging (MRI), T1-weighted sequences each have a homogenized signal. On axial T2-weighted sequences they exhibit a target sign, with high signal intensity at the edge and intermediate signal centrally. concerning five-hitter of those tumors undergo malignant degeneration and concerning 1/2 these square measure seen in patients with sort one neurofibromatosis. Malignant peripheral nerve sheath tumors are generally larger than their benign counterpart and demonstrate rise with central necrosis. Benign neurogenic tumor in posterior mediastinum SIGNS AND SYMPTOMS Tumors are typically found during a chest X-ray that was ordered to diagnose another health condition. If symptoms develop, it’s often because the tumor is pushing on surrounding organs. Symptoms can include: cough shortness of breath chest pain fever/chills night sweats coughing up blood unexplained weight loss swollen lymph nodes respiratory blockage hoarseness ACCESSING THE PATIENT Questions to Ask the patient Mediastinal masses may be symptomatic or asymptomatic, it is necessary to ask the patient about: Any recent respiratory symptoms (dyspnea, cough) Dysphagia Systemic/constitutional symptoms (fever, weight loss, night sweats) Facial swelling Hoarseness of breath History Past surgeries Known congenital defects Recent chest trauma Recent or recurrent pulmonary infections Procedures for Investigation A complete physical exam must be performed including growth parameters. Close attention should be paid to the patient’s stability as well as examination of the chest, abdomen and lymph nodes. Note any: Respiratory distress or cyanosis Hoarseness Symptoms of Horner’s syndrome (ptosis, miosis, decreased sweating) Facial/upper limb edema and venous distension in neck and upper limbs/chest Lymphadenopathy Hepatomegaly, Splenomegaly During radiographic investigation it is important to consider the following: Where is the lesion? How solid is the lesion? Is the lesion diffuse or well-circumscribed? INVESTIGATIONS Chest X-ray: An initial investigation and often how a mediastinal mass is first incidentally detected in the asymptomatic patient MRI: No radiation needed but control of breath necessary for MRI is difficult with infants CT Scan: Highly effective at identifying lesions A CT scan is often sufficient for the identification of the lesion location. A chest CT scan showing big mediastinal cyst on the anterior side Mediastinoscopy with biopsy (Performed under general anesthesia, this examination of the chest cavity utilizes a lit tube embedded through a little entry point under the mid-section bone; a specimen of tissue is taken to figure out whether malignancy is available. Mediastinoscopy with biopsy permits specialists to precisely analyze 80 to 90% of mediastinal tumors, and 95 to 100% of anterior mediastinal tumors.) THORACOTOMY. although a few specialists still perform this methodology to analyze mediastinal tumors, thoracoscopy might be utilized rather as a part of specific circumstances. In a thoracotomy , the doctor accesses the chest cavity by slicing through the chest wall. Thoracotomy takes into consideration study, examination, treatment, or evacuation of any organs in the chest hole. Tumors and metastatic developments can be evacuated, and a biopsy can be taken, through the entry point. Thoracotomy likewise offers access to the heart, throat, stomach, and the segment of the aorta that goes through the mid-section cavity. This 100% exact, insignificantly invasive strategy is performed under general anesthesia. enabling the specialist to see the whole mediastinum, thoracoscopy might be utilized when a mediastinal tumor touches the mediastinal pleura. In any case, this system has constrained applications. Thoracoscopy can't be performed on a patient who has thick scar tissue. OTHER INVESTIGATIONS CBC and differential with peripheral smear Thyroid function (if mediastinal goiter present) Calcium, phosphate PTH 24 hour metanephrines and catecholamine Alpha fetoprotein and/or beta HCG Once a mediastinal mass has been identified the next step is decide whether the lesion should be observed, aspirated, biopsied or excised. In cases of suspected lymphoma, germ-cell tumour or unresectable invasive malignancy, a diagnostic biopsy and not complete excision is the procedure of choice. If the mass is suspected to be a thymoma, teratoma and most benign lesions, excision of the mass is indicated. DIFFERENTIAL DIAGNOSIS Neoplasm Lymphoma Most common pediatric mediastinal malignancy Includes Hodgkin’s and Non-Hodgkin’s lymphoma Hodgkin’s lymphoma is responsible for 7% childhood cancers Seen in all parts of mediastinum Neurogenic Ganglioma, ganglioneuroblastoma, neuroblastoma, paraganglioma Most common benign lesions 2nd most common malignant lesions Most often in posterior mediastinum Thymoma Anterior mediastinum Germ Cell Neoplasms (i.e. teratomas or seminomas) Benign and Malignant Hemangiomas Rare Non-neoplastic Bronchogenic or enterogenic cysts Congenital duplication cysts Thymic cysts Thymic hyperplasia Infection Sarcoidosis Vascular defects (i.e. aortic aneurysm) TREATMENT The treatment utilized for mediastinal tumors relies on upon the kind of tumor and its area: Thymomas A patient whose thymoma is surgically taken out (resected) has the most obvious chance of survival. To diminish the probability of new tumors creating (reseeding), specialists don't prescribe biopsy, and attempt to evacuate the tumor without puncturing the container that walls it in. RADIATION. Thymomas react well to radiation, which is utilized: to treat all phases of sickness before or after surgical resection to treat repetitive disease. The course of treatment keeps going three to six weeks. The most widely recognized intricacies of radiation treatment are development of scar tissue in the lungs (pulmonary fibrosis), inflammation of the pericardium (pericarditis), and aggrevation of the spinal string (myelitis). CHEMOTHERAPY. The utilization of chemotherapy to treat intrusive thymomas is turning out to be more regular. One or more medications is given before or after surgery. Engineered hormones (corticosteroids ) can invert the movement of tumors that don't react to chemotherapy. Teratomas Teratomas are evacuated surgically. Chemotherapy and radiation are not used to treat these tumors. The prospect for long haul cure is incredible, and these tumors once in a while repeat. Lymphomas These tumors don't require surgery, but to make the determination. Specialists treat them with chemotherapy and radiation. Thyroid tumors Specialists generally treat thyroid tumors with surgical resection, chemotherapy, and/or radiation. Fibrosarcomas Fibrosarcomas can't generally be resected and don't react well to chemotherapy. Threatening schwannomas Multiagent chemotherapy is utilized to treat these aggressive tumors, which have a tendency to repeat after surgery. The 5-year survival rate is 75%. Neuroblastomas Since these tumors at times relapse suddenly, specialists might defer treatment if: the patient has no manifestations or the tumor is not developing. In different cases, specialists uproot these tumors even before manifestations show up. Dangers connected with expelling these tumors from the spinal channel include: harm to the spinal line or front spinal corridor uncontrolled seeping in the spinal trench diminished blood supply (ischemia) to tissues and organs. What are the advantages of insignificantly intrusive surgery to treat mediastinal tumors? As with conventional surgery, patients who experience minimal obtrusive surgery, for example, video-helped thoracoscopy (VATS) mediastinoscopy, experience: Diminished postoperative torment Shorter hospital time More fast recuperation and back to work Other conceivable advantages incorporate lessened danger of disease and lower mortality. ANESTHESIA FOR MEDIASTINAL MASS Management for mediastinal mass In the event of airway obstruction during injection of general anesthesia,the standard algorithm should be applied.if ventilation cannot be accomplished despite tracheal tube placement,perform the following steps Push the endotracheal tube sidtally past the tracheal obstruction or into the right main bronchus.if the endotracheal tube cannot be advanced past the obstruction,rigid brinchoscopy should be perfomed If the above measures are unsuccessful in restoring oxygenation or circulation,immediately institute cardiopulmonary bypass What are the dangers of negligibly obtrusive surgery to treat mediastinal tumors? There are complexities of radiation, chemotherapy and surgical treatment of mediastinal tumors. The conceivable complications of insignificantly obtrusive surgical treatment include: Harm to the encompassing region, which might incorporate the heart, pericardium (the heart's coating) or spinal cord. Pleural effusion (a gathering of liquid between the thin layers of tissue covering the lung and the mass of the chest cavity, or pleura) Postoperative drainage Postoperative contamination or bleeding CHEST RADIOGRAPH AND COMPUTER TOMOGRAPHY IMAGES Right sided mediastinal mass in 6 month old baby Sagital T2 weighted images, Note extension of the mediastinal mass into the spinal canal. T2 weighted MRI, hyperintense right sided mediastinal mass displacing the thymus superiorly and the heart into the left side of the thorax. 19 year old girl chest radiograph Large B-cell NHL presented as lobulated left anterior mediastinal mass many myeloma seen as mediastinal mass Ct scan of 22 year old woman Chest CT shows a mass in the in the right posterior superior mediastinum.