A mediastinal tumor is a

tumor A neoplasm () is a type of abnormal and excessive growth of tissue. The process that occurs to form or produce a neoplasm is called neoplasia. The growth of a neoplasm is uncoordinated with that of the normal surrounding tissue, and persists ...

in the

mediastinum The mediastinum (from ;: mediastina) is the central compartment of the thoracic cavity. Surrounded by loose connective tissue, it is a region that contains vital organs and structures within the thorax, mainly the heart and its vessels, the eso ...

, the cavity that separates the

lung The lungs are the primary Organ (biology), organs of the respiratory system in many animals, including humans. In mammals and most other tetrapods, two lungs are located near the Vertebral column, backbone on either side of the heart. Their ...

s from the rest of the chest. It contains the

heart The heart is a muscular Organ (biology), organ found in humans and other animals. This organ pumps blood through the blood vessels. The heart and blood vessels together make the circulatory system. The pumped blood carries oxygen and nutrie ...

esophagus The esophagus (American English), oesophagus (British English), or œsophagus (Œ, archaic spelling) (American and British English spelling differences#ae and oe, see spelling difference) all ; : ((o)e)(œ)sophagi or ((o)e)(œ)sophaguses), c ...

trachea The trachea (: tracheae or tracheas), also known as the windpipe, is a cartilaginous tube that connects the larynx to the bronchi of the lungs, allowing the passage of air, and so is present in almost all animals' lungs. The trachea extends from ...

thymus The thymus (: thymuses or thymi) is a specialized primary lymphoid organ of the immune system. Within the thymus, T cells mature. T cells are critical to the adaptive immune system, where the body adapts to specific foreign invaders. The thymus ...

, and

aorta The aorta ( ; : aortas or aortae) is the main and largest artery in the human body, originating from the Ventricle (heart), left ventricle of the heart, branching upwards immediately after, and extending down to the abdomen, where it splits at ...

. The most common mediastinal masses are thymoma (20% of mediastinal tumors), usually found in the anterior mediastinum, followed by neurogenic Timor (15–20%) located in the anterior mediastinum.

Lung cancer Lung cancer, also known as lung carcinoma, is a malignant tumor that begins in the lung. Lung cancer is caused by genetic damage to the DNA of cells in the airways, often caused by cigarette smoking or inhaling damaging chemicals. Damaged ...

typically spreads to the

lymph node A lymph node, or lymph gland, is a kidney-shaped organ of the lymphatic system and the adaptive immune system. A large number of lymph nodes are linked throughout the body by the lymphatic vessels. They are major sites of lymphocytes that includ ...

s in the mediastinum. The mediastinum has three main parts: the anterior mediastinum (front), the middle mediastinum, and the posterior mediastinum (back). Masses in the anterior portion of the mediastinum can include thymoma,

lymphoma Lymphoma is a group of blood and lymph tumors that develop from lymphocytes (a type of white blood cell). The name typically refers to just the cancerous versions rather than all such tumours. Signs and symptoms may include enlarged lymph node ...

pheochromocytoma Pheochromocytoma is a rare tumor of the adrenal medulla composed of chromaffin cells and is part of the paraganglioma (PGL) family of tumors, being defined as an intra-adrenal PGL. These neuroendocrine tumors can be sympathetic, where they relea ...

germ cell tumor A germ cell tumor (GCT) is a neoplasm derived from primordial germ cells. Germ-cell tumors can be cancerous or benign. Germ cell tumors typically originate from the gonads (ovary and testis), but can arise in other areas of the body. Extragon ...

s including

teratoma A teratoma is a neoplasia, tumor made up of several types of biological tissue, tissue, such as hair, muscle, Human tooth, teeth, or bone. Teratomata typically form in the tailbone (where it is known as a sacrococcygeal teratoma), ovary, or test ...

, thyroid tissue, and parathyroid lesions. Masses in this area are more likely to be

malignant Malignancy () is the tendency of a medical condition to become progressively worse; the term is most familiar as a characterization of cancer. A ''malignant'' tumor contrasts with a non-cancerous benign tumor, ''benign'' tumor in that a malig ...

than those in other compartments. Masses in 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.

Types

Thymoma

Most common primary anterior mediastinal tumor (20%) in adults but rarely seen in children. It can be classified as lymphocytic, epithelial, or spindle cell histologies, but the clinical significance of these classifications is controversial. Tonofibrils seen under electron microscopy can differentiate thymoma from other tumors such as carcinoid, Hodgkin's, and seminoma. Patients are usually asymptomatic but can present with myasthenia gravis-related symptoms, substernal pain, dyspnea, or cough. Invasive tumors can produce compression effects such as superior vena cava syndrome. Thymomas are diagnosed with CT or MRI revealing a mass in anterior mediastinum. Therapy in stage I tumors consists of surgical resection with good prognosis. Stage II–III requires maximal resection possible followed by radiation. Stage IV disease requires addition of cisplatin-based chemotherapy in addition to those in stage II and III. For those with invasive thymoma, treatment is based on induction chemotherapy, surgical resection, and post-surgical radiation. 5-year survival for invasive thymoma is between 12 and 54% regardless of any myasthenia gravis symptoms.

Lymphoma

Second most common primary anterior mediastinal mass in adults. Most are seen in the anterior compartment and rest are seen in middle compartment.

Hodgkin's lymphoma Hodgkin lymphoma (HL) is a type of lymphoma in which cancer originates from a specific type of white blood cell called lymphocytes, where multinucleated Reed–Sternberg cells (RS cells) are present in the lymph nodes. The condition was named a ...

usually present in 40–50's with nodular sclerosing type (7), and non-Hodgkin's appears in all age groups. There is also

primary mediastinal B-cell lymphoma Primary mediastinal B-cell lymphoma, abbreviated PMBL or PMBCL, is a rare type of lymphoma that forms in the mediastinum (the space in between the lungs) and predominantly affects young adults. While it had previously been considered a subtype of ...

with exceptionally good prognosis. Common symptoms of a mediastinal lymphoma of include

fever Fever or pyrexia in humans is a symptom of an anti-infection defense mechanism that appears with Human body temperature, body temperature exceeding the normal range caused by an increase in the body's temperature Human body temperature#Fever, s ...

weight loss Weight loss, in the context of medicine, health, or physical fitness, refers to a reduction of the total body mass, by a mean loss of fluid, body fat (adipose tissue), or lean mass (namely bone mineral deposits, muscle, tendon, and other conn ...

night sweats Night sweats or nocturnal hyperhydrosis is the repeated occurrence of excessive sweating during sleep. The person may or may not also perspire excessively while awake. One of the most common causes of night sweats in women over 40 is the horm ...

, and compressive symptoms such as pain, dyspnea, wheezing,

Superior vena cava syndrome Superior vena cava syndrome (SVCS), is a group of symptoms caused by obstruction of the superior vena cava ("SVC"), a short, wide vessel carrying circulating blood into the heart. The majority of cases are caused by malignant tumors within the me ...

pleural effusion A pleural effusion is accumulation of excessive fluid in the pleural space, the potential space that surrounds each lung. Under normal conditions, pleural fluid is secreted by the parietal pleural capillaries at a rate of 0.6 millilitre per kilog ...

s. Diagnosis usually by CT showing lobulated mass. Confirmation done by tissue biopsy of accompanying nodes if any,

mediastinoscopy Mediastinoscopy is a procedure that enables visualization of the contents of the mediastinum, usually for the purpose of obtaining a biopsy. Mediastinoscopy is often used for staging of lymph nodes of lung cancer or for diagnosing other condition ...

mediastinotomy Mediastinoscopy is a procedure that enables visualization of the contents of the mediastinum, usually for the purpose of obtaining a biopsy. Mediastinoscopy is often used for staging of lymph nodes of lung cancer or for diagnosing other condition ...

, or

thoracotomy A thoracotomy is a surgical procedure that involves cutting open the chest wall to gain access into the pleural cavity, It is mostly performed by specialist cardiothoracic surgeons, although emergency physicians or paramedics occasionally also ...

. FNA biopsy is usually not adequate. Treatment of mediastinal Hodgkin's involves chemotherapy and/or radiation. 5 year survival is now around 75%. Large-cell type may have somewhat better prognosis. Surgery is generally not performed because of invasive nature of tumor. Of all cancers involving the same class of blood cell, 2% of cases are mediastinal large B cell lymphomas.

Diagnosis

In several editions of Physical Diagnosis, concerning mediastinal tumors the author writes: :''According to Christian¹ the mediastinal neoplasms which are neither so rare nor so obscure as to make

diagnosis Diagnosis (: diagnoses) is the identification of the nature and cause of a certain phenomenon. Diagnosis is used in a lot of different academic discipline, disciplines, with variations in the use of logic, analytics, and experience, to determine " ...

practically impossible are: (1)

Sarcoma A sarcoma is a rare type of cancer that arises from cells of mesenchymal origin. Originating from mesenchymal cells means that sarcomas are cancers of connective tissues such as bone, cartilage, muscle, fat, or vascular tissues. Sarcom ...

(including lymphosarcoma, leucaemic growths, and Hodgkins' disease; (2)

Teratoma A teratoma is a neoplasia, tumor made up of several types of biological tissue, tissue, such as hair, muscle, Human tooth, teeth, or bone. Teratomata typically form in the tailbone (where it is known as a sacrococcygeal teratoma), ovary, or test ...

and cyst.'' Many signs and symptoms of a mediastinal tumor do not distinguish between these two principal classes of mediastinal tumor. However, on a

radiograph Radiography is an imaging technique using X-rays, gamma rays, or similar ionizing radiation and non-ionizing radiation to view the internal form of an object. Applications of radiography include medical ("diagnostic" radiography and "therapeu ...

usually the former class will have an irregular shape and the latter class will have a smooth spherical or ovoid shape. A large minority of patients with a mediastinal teratoma (including

dermoid cyst A dermoid cyst is a teratoma of a cystic nature that contains an array of developmentally mature, solid tissues. It frequently consists of skin, hair follicles, and sweat glands, while other commonly found components include clumps of long hair ...

) will cough up hair. For a differential diagnosis, the key is to exclude

aneurysm An aneurysm is an outward :wikt:bulge, bulging, likened to a bubble or balloon, caused by a localized, abnormal, weak spot on a blood vessel wall. Aneurysms may be a result of a hereditary condition or an acquired disease. Aneurysms can also b ...

References

External links