Sandbox:Trusha

IEditor-In-Chief: C. Michael Gibson, M.S., M.D. [2] Associate Editor(s)-in-Chief: Trusha Tank, M.D.[3]

Differential diagnosis of mediastinal mass

Wide variety of medical conditions can present as a mediastinal mass on radiological imaging.

• Mediastinal mass may cause obstruction, entrapment or infiltration of other mediastinal organs such as: Trachea, bronchi, esophagus, aorta, superior vena cava (SVC) or heart.
• Disorder caused by any kind of mediastinal mass is collectively known as: Mediastinal syndromes
• Mediastinal syndrome includes:
  • Compression of the trachea: Dyspnea and respiratory insufficiency.
  • Compression of the esophagus: Dysphagia.
  • Compression of SVC causes superior vena cava syndrome: Vein distention, edema of the face or upper extremities and a positive Pemberton's sign.
    • Pemberton's sign: Development of suffusion, plethora, or duskiness upon elevation of the arms above the head in patient
    • Superior vena cava syndrome is the most severe complication of mediastinal syndrome and a medical emergency.

ABBREVIATIONS: N/A: Not available, SOB: Shortness of breath, M/C: Most common, RI: Respiratory insufficiency, NM: Neuromuscular system, SVCS: Superior vena cava syndrome, SLE: Systemic lupus erythematosus disease, T3: Triiodothyronine, T4: Thyroxine, TSH: Thyroid stimulating hormone, TFT: Thyroid function test
Class	Disease	Etiology	Clinical presentation				Paraclinical findings
			General symptoms	Mediastinal syndrome
				Dyspnea/ RI	Dysphagia	SVCS	Gold standard	Image	Additional findings
Anterior mediastinal mass
Tumors	Thymoma	Human foamy virus Epstein-Barr virus Human T-cell lymphotropic virus MEN 1 syndrome	Cough wheezing Chest pain Muscle weakness (MG) Anemia	+	+	+	Biopsy: Epithelial cells Immature lymphocytes Immature T cells		Associated condition NM Myasthenia gravis Neuromyotonia Rippling muscle disease Polymyositis/dermatomyositis Encephalitis (limbic, cortical and brain stem) Intestinal pseudoobstruction Hematological Anemia: pure red cell aplasia, pernicious anemia, hemolytic anemia, aplastic anemia Other isolated cytopenias: eosinophils, basophils neutrophils Immunodeficiencies: hypogammaglobulinemia/- T-cell deficiencies (Good syndrome) Dermatological Pemphigus (foliaceus or paraneoplastic) Lichen planus Alopecia areata Endocrine Addison disease Grave's disease Cushing's disease Hepato-renal Glomerulonephritis Autoimmune hepatitis Systemic Autoimmune Diseases SLE Sjögren's syndrome Systemic sclerosis Graft-versus-host disease
	Disease	Etiology	Symptoms	Dyspnea/ RI	Dysphagia	SVCS	Gold standard	Image	Additional findings
	Fatty mass	Steroid use Cushing's syndrome Obeses	Mostly asymptomatic	-	-	-	MRI: Well-defined encapsulated mas Extensive fat content Small amounts of solid areas Fibrous septa		Fatty mass can be: Lipoma Liposarcoma Thymolipoma
	Non-Hodgkin lymphoma	Age (above 60 years) Caucasians > African and Asian Americans Positive family history of first degree relative B-cell activating autoimmune disorders Radiation exposure Infections (HIV, Hep C, HTLV-1, EBV, HHV-8, H. pylori, psittacosis, Campylobacter jejuni) Previous cancer treatment Exposure to chemicals and drugs (pesticides, methotrexate, TNF inhibitors, trichloroethylene) Cigarette smoking for ≥ 40 years BMI ≥30 kg/m2 Diet Hair dyes Breast implants	Painless lymphadenopathy Fever Weight loss and anorexia Night sweats Constant fatigue Itchy skin Cough Shortness of breath Abdominal pain or swelling Constipation Nausea Vomiting Headache Personality changes Seizures	+/-	+/-	+/-	Excisional lymph node biopsy with immunohistochemical study CD 20+ cells		Anemia: Involvement of bone marrow Autoimmune hemolysis and bleeding Thrombocytopenia, leukopenia, or pancytopenia Lymphocytosis with malignant cell Thrombocytosis
	Disease	Etiology	Symptoms	Dyspnea/ RI	Dysphagia	SVCS	Gold standard	Image	Additional findings
	Teratoma	Benign equal in men and women Malignant more common in men Pediatric population higher risk	Benign Asymptomatic Malignant Cough Chest pain Trichoptysis	+/-	+/-	+/-	Chest CT scan: Location Metastasis Intrinsic structure Soft tissue Fat Calcification		N/A
Thyroid disease	Thyroid cancer	Hx of goiter Family Hx of thyroid disease Female gender Asian race Radiation exposure MEN syndrome	Lump in the neck Dysphonia Lymphadenopathy Cough Sore throat Neck pain	+	+	-	US guided biopsy: Papillary thyroid cancer Follicular thyroid cancer Medullary thyroid cancer Anaplastic thyroid cancer Lymphoma		TFT Elevated T3 Elevated T4 Low TSH
	Goiter	Iodine deficiency Female gender Age over 50 years Personal or family history Certain medications Immunosuppressants Antiretrovirals Amiodarone Lithium Radiation	A visible swelling at the base of your neck Tight feeling in throat Cough Hoarseness Fatigue	+	+	-	Radioactive iodine scan: Nodules Size Function of the gland: ↑ or ↓		Hyperavtive gland (hyperthyroid): Grave's disease Hypoactive gland (hypothyroid): Hashimoto thyroiditis Normal functioning gland (euthyroid): Benign thyroid enlargement (non toxic multinodular goiter)
Class	Disease	Etiology	Symptoms	Dyspnea/ RI	Dysphagia	SVCS	Gold standard	Image	Additional findings
Middle mediastinal mass
CVS disease	Pericardial effusion	Acute myocardial infarction Aortic dissection Aortic rupture Myocardial rupture Rupture of ventricular aneurysm Uremic pericarditis Rheumatic pericarditis Tuberculous pericarditis Uremic pericarditis Viral pericarditis Dressler's syndrome Cardiac catheterization Cardiomyopathy Chemotherapy Chest trauma Collagen vascular disease Congestive heart failure Neoplasm Postpericardiotomy syndrome Postirradiation	Chest pain The positional change affecting the chest pain Orthopnea Fever symptoms of infection, injury or systemic disease causing the effusion	+	+/-	-	Echocardiography guided pericardiocentesis: Therapeutic Diagnostic pericardial disease Hemodynamic parameters Volume Effusion content (blood/exudate/transudate) Microbial culture		Physical findings: Pulsus paradoxus Hypotension in cardiac tamponade Jugular venous distension with a prominent Y descent Kussmaul's sign EKG: Electrical alternans Echo: Presence of effusion Reversal of RA and RV diastolic trans-mural pressures Cardiac chamber indentation or collapse Respiratory variation of atrioventricular valves increased.
	Aortic dissection	Atherosclerosis Chest trauma Chronic hypertension Complication of cardiac procedures Connective tissue disorders Vasculitis Advanced age Smoking Dyslipidaemia Cocaine Connective tissue disorders	Severe acute chest pain Back pain Pain radiating to neck, throat, jaw, and/or unilateral face Abdominal pain Claudication Hemoptysis Horner syndrome Oliguria/ Anuria Paraplegia, paralysis Hoarseness	+	+/-	+	MRI: Location of the intimal tear Involvement of branches of aorta Other vascular pathology		TEE: Identify true and false lumens Intimal flap Thrombosis in the false lumen Pericardial effusion Aortic regurgitation Proximal coronaries CTA: Beak sign: An acute angle between the dissection flap and the arterial wall Aortic cobwebs: Fibroelastic bands Size: False lumen larger than the true lumen Displaced intimal calcification: True lumen
	Disease	Etiology	Symptoms	Dyspnea/ RI	Dysphagia	SVCS	Gold standard	Image	Additional findings
	Superior vena cava obstruction	Compression of SVC from: Aortic aneurysm Bronchogenic carcinoma Breast cancer Cystic hygroma Goiter Histoplasmosis Indwelling catheter Lung cancer Lymphoma Non Hodgkin's lymphoma Small cell lung cancer Thymoma Tuberculosis	Cough Hoarseness Chest pain Problems swallowing and/or talking Hemoptysis Headache Dizziness Decreased alertness Dizziness Fainting Sensation of head or ear "fullness" Vision changes	+	+	++	Contrast-enhanced CT scan: Location and severity of the obstruction Superimposed thrombosis Mediastinal mass or lymphadenopathy Collateral vessels and associated lung masses		Invasive contrast venography: Etiology of obstruction Exact location of the obstruction
	Partial anomalous pulmonary venous connection	Uncommon congenital abnormality Associated with an ASD Turner's syndrome (monosomy X) The scimitar syndrome	Asymptomatic Episodic exertional dizziness Neck pain Diaphoresis	+	-	-	MRI with contrast: Provide better anatomic definition Associated defects Condition of heart chambers		Associated with Adult onset pulmonary arterial hypertension (PAH) Right ventricular volume overload (RV failure) Cardiac catheter: Pressure and O2 Sat in heart chambers PFT: Normal despite of severe SOB
GI disease	Esophageal achalasia	Idiopathic Chagas disease Gastric carcinoma Herpes zoster HSV-1 Measles virus Paraneoplastic syndrome Sarcoidosis	Dysphagia for solids and liquids of patients respectively Regurgitation of undigested food Cough Aspiration Weight loss Chest pain, radiate to the back, jaw, neck, and arms Heartburn Hiccup Difficulty belching	+	+	-	High resolution manometry (HRM): Residual pressure of LES > 10 mmHg Incomplete relaxation of the LES. Increased resting tone of LES Aperistalsis High intra-esophageal pressure (due to stasis of food)		X ray: "Bird's beak image" or "rat tail" appearance Dilated esophageal body Air fluid level due to absent peristalsis Absence of gastric air bubble In advanced achalasia - sigmoid appearance CT scan: Dilatation of the esophagus Air fluid levels Exclude pseudoachalasia Echalasia symptoms resulting from esophageal cancer
	Disease	Etiology	Symptoms	Dyspnea/ RI	Dysphagia	SVCS	Gold standard	Image	Additional findings
	Esophageal cancer	Age over 60 Male gender Smoking Alcohol consumption Obesity Lye Ingestion Nitrosamine in food Plummer-Vinson syndrome Tylosis or Howel-Evans syndrome Radiation therapy GERD Barrett's esophagus Achalasia	Dysphagia to solid food Heartburn Weight loss Changes in diet Anorexia Regurgitation of food or saliva Hoarseness or loss of voice Intractable cough Blood in stools Frequent pneumonia	-	+	-	Endoscopy with biopsy: Friable lesion Superficial plaques Superfcial nodules Superficial ulcerations Strictures Ulcerated mass Circumferential masses		Barium swallow: Tapering stricture known as a "rat's tail" Irregular stricture Pre-stricture dilatation Shouldering CT scan: Eccentric or circumferential wall thickening >5 mm Peri-esophageal soft tissue and fat stranding Dilated fluid and debris filling the esophageal lumen Tracheobronchial invasion Aortic invasion
	Esophageal rupture	Seizures Severe straining Vomiting Childbirth Prolonged coughing or laughing	Mackler's triad: Chest pain Vomiting Subcutaneous emphysema Other: Odynophagia Fever Tachypnea Tachycardia Cyanosis, and hypotension Pleural effusion Patients with cervical perforations can present with Neck pain Dysphonia	+	+	-	Esophagogram: The location Extent of perforation		CT scan: Esophageal wall edema and thickening Peri-esophageal fluid Mediastinal widening Air and fluid in the pleural spaces, retroperitoneum, or lesser sac
	Hiatus hernia	50 or older age Obesity Female > Male Trauma: when undergoing surgery Frequent coughing Straining with constipation Heavy lifting Congenital Smoking Stress	Nausea Vomiting Regurgitation Heart burn Regurgitation Dysphagia	-	+	-	High resolution manometry with esophageal pressure topography (EPT): Evidence of separation of the crural diaphragm from the lower esophageal sphincter(LES) Real-time localization of the gastroesophageal junction Identification of intermittent herniation		Ultrasound: Location of gastroesophageal junction Bowel diameter measured at the diaphragmatic hiatus Ultrasound in pediatric population: Measurement of intra-abdominal esophagus which is less than 2 cm in diameter Sign of a beak at the gastroesophageal junction CT scan: Retrocardiac air-fluid level Organs within the hernia sac Focal fat collection in the middle of the mediastinum Visualise contents, length, orientation of herniated stomach inside the lower thorax Herniated contents lie adjoining to the esophagus Widening of esophageal hiatus Dehiscence of diaphragmatic crura (>15 mm)
Class	Disease	Etiology	Symptoms	Dyspnea/ RI	Dysphagia	SVCS	Gold standard	Image	Additional findings
Pulmonary disease	Hilar lymphadenopathy	Lymphadenopathy and tumors - rounded/lobular, nonbranching structures in which the radiopacity abruptly diminishes at the margin of the tumor or lymph node Pulmonary venous hypertension - enlargement of the superior pulmonary veins causes increased vascular density in the upper half of the hilum. Important causes of pulmonary venous hypertension are left ventricular failure, mitral stenosis, or mitral regurgitation Pulmonary arterial hypertension - central pulmonary arteries are dilated causing hilar enlargement with a branching appearance with peripheral pruning due to abrupt tapering of vessels. The causes of pulmonary arterial hypertension may be primary or secondary to lung diseases such as chronic obstructive pulmonary disease (COPD) Increased pulmonary blood flow - increased central and peripheral pulmonary vascular markings (peripheral lung markings become visible in the peripheral 1-2 cm of the lung). Increased pulmonary blood flow of two to three times greater than normal is required to make it radiologically visible. The mechanisms of increased pulmonary blood flow are left-to-right intracardiac shunts and hyperdynamic circulation. Unilateral or bilateral asymmetrical Lymphadenopathy Unilateral or bilateral asymmetric lymphadenopathy is the most important and challenging cause of unequal hilum that concern every pulmonologist. Important causes of hilar lymphadenopathy are: Tuberculosis - TB is the most important cause of asymmetric hilum particularly in our country. Hilar lymphadenopathy occurs as a major component of primary TB, usually occurs in children. Tubercular hilar lymphadenopathy may occur in adult particularly in immunocompromised persons (human immunodeficiency virus (HIV) infection) Bronchogenic carcinoma - most important cause of unequal hilum in adult. It may be due to spread to hilar lymph node or due to growth itself Lymphoma - usually causes bilateral hilar lymphadenopathy and may be unequal. Peripheral lymphadenopathy, a usual finding of lymphoma, may be absent and in that situation diagnosis becomes difficult Sarcoidosis - usually causes bilateral symmetrical hilar lymphadenopathy, but sometimes it may be asymmetric Other causes - infection caused by fungal, atypical mycobacteria, viral, tularemia, and anthrax may cause unilateral hilar enlargement. Silicosis, drug reaction, etc., are the other rare causes of unequal hilum.
	Pneumomediastinum
	Sarcoidosis
Mediastinal tumor	Mediastinal tumor
	Mediastinal germ cell tumor
Infection	Mediastinitis
	Anthrax
	Tularemia
Cystic disease	Dermoid cyst
	Bronchogenic cyst
Chronic inflammatory	Churg-Strauss syndrome
Class	Disease	Etiology	Symptoms	Dyspnea/ RI	Dysphagia	SVCS	Gold standard	Image	Additional findings
Posterior mediastinal mass
CNS disease	Meningocele
	Neurilemmoma
ABBREVIATIONS: N/A: Not available, SOB: Shortness of breath, M/C: Most common, RI: Respiratory insufficiency, NM: Neuromuscular system, SVCS: Superior vena cava syndrome, SLE: Systemic lupus erythematosus disease, T3: Triiodothyronine, T4: Thyroxine, TSH: Thyroid stimulating hormone, TFT: Thyroid function test

1. Superior vena cava obstruction
2. Partial anomalous pulmonary venous connection
3. Esophageal achalasia
4. Esophageal cancer
5. Esophageal rupture
6. Hiatus hernia
7. Hilar lymphadenopathy
8. Pneumomediastinum
9. Sarcoidosis
10. Lymphoma
11. Neurilemmoma
12. Non-Hodgkin lymphoma
13. Teratoma
14. Thymoma

1. Thyroid cancer
2. Goitre
3. Mediastinal germ cell tumor,
4. Mediastinal tumor,
5. Mediastinitis

1. Churg-Strauss syndrome
2. Bronchogenic cyst,
3. Dermoid cyst
4. Anthrax:
5. Tularemia

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CT scan showing a smooth anterior mediastinal mass, with a mixed internal density of containing both enhancing soft tissue and cystic areas. The outline of the mass is relatively well defined. No lymphadenopathy, pleural effusion or infiltration. Case courtesy of Dr. Abdallah Al Khateeb (Picture courtesy: Radiopedia)

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CT scan showing excessive fatty tissue deposition within the posterior mediastinum with anterior displacement of the esophagus. Case courtesy of Dr. Ahmed Abdrabou (Picture courtesy: [1])