Basics
Description
Space-occupying lesion of the mediastinum
- Anterior mediastinum includes the thymus and other structures anterior to the pericardium.
- Middle mediastinum contains the heart, great vessels, ascending aorta, and aortic arch, as well as lymph nodes.
- Posterior mediastinum contains the tracheobronchial tree, esophagus, descending aorta, and neural structures.
Pathophysiology
Morbidity is due to compression of adjacent normal structures, particularly large airways, heart, and great vessels.
Diagnosis
Differential Diagnosis
- Congenital/anatomic
- Large normal thymus in neonate (anterior)
- Bronchogenic, pericardial, or foregut cyst (middle)
- Aortic aneurysm and other vascular anomalies (middle)
- Thoracic meningocele (posterior)
- Infectious (may cause mediastinal adenopathy and/or pulmonary nodules) (middle/posterior)
- Tuberculosis
- Histoplasmosis
- Aspergillosis
- Coccidioidomycosis
- Blastomycosis
- Foreign body in the trachea or esophagus
- Sarcoidosis
- Tumor
- Benign
- Thymoma (anterior)
- Teratoma/dermoid cyst (anterior)
- Lymphangioma/cystic hygroma (middle/posterior)
- Hemangioma (middle/posterior)
- Ganglioneuroma (posterior)
- Neurofibroma (posterior)
- Malignant
- Malignant germ cell tumor (anterior)
- Hodgkin lymphoma (anterior/middle)
- Non-Hodgkin lymphoma or leukemia (anterior/middle)
- Neuroblastoma (posterior)
- Ganglioneuroblastoma (posterior)
- Ewing sarcoma or osteogenic sarcoma (anterior/posterior)
- Pheochromocytoma (posterior)
- Neurofibrosarcoma (posterior)
- Rhabdomyosarcoma or pleuropulmonary blastoma (any)
Approach to the Patient
Goal is to quickly establish diagnosis and begin treatment as indicated, as condition may rapidly progress and become life threatening. If malignancy is suspected, the child should be immediately referred to an oncologist.
History
- Question: systemic symptoms (fever, weight loss, night sweats, fatigue)?
- Significance: may be associated with infection or malignancy
- Question: cough, wheeze, dyspnea on exertion, orthopnea?
- Significance: may indicate early airway compromise
- Question: face/neck swelling?
- Significance: suggests superior vena cava syndrome
Physical Exam
Focused attention for signs of respiratory distress or cardiovascular compromise. Check for signs and symptoms noted below.
- Finding: edema/suffusion of face and neck, jugular venous distension, conjunctival injection, headache, altered mental status?
- Significance: superior vena cava syndrome
- Finding: cough (nonproductive), orthopnea or dyspnea, stridor, or wheezing?
- Significance: airway compression
- Finding: quiet heart sounds, hypotension, narrowed pulse pressure, or pulsus paradoxus?
- Significance: cardiac tamponade/diastolic dysfunction secondary to mass effect
- Finding: lymphadenopathy or hepatosplenomegaly?
- Significance: malignancy or infection. Low cervical, posterior, or supraclavicular adenopathy particularly concerning for malignancy
- Finding: pallor, ecchymoses, petechiae, and/or mucosal bleeding?
- Significance: suggest anemia and thrombocytopenia, which are seen in malignant conditions also infiltrating the bone marrow
- Finding: Horner syndrome
- Significance: posterior mediastinal mass, most commonly a neuroblastoma
Diagnostic Tests & Interpretation
- Test: CBC with differential.
- Significance: anemia, thrombocytopenia, and neutropenia noted in malignant diseases infiltrating bone marrow. Circulating blasts frequently noted in leukemia or lymphoma; leukocytosis in infection
- Test: lactate dehydrogenase, uric acid, electrolytes, calcium, phosphate, creatinine
- Significance: tumor lysis screen
- Test: purified protein derivative (PPD) skin test
- Significance: tuberculosis
- Test: urine vanillylmandelic acid (VMA) and homovanillic acid (HVA)
- Significance: elevated in 90% of children with neuroblastoma
- Test: alpha-fetoprotein and beta-hCG
- Significance: can be elevated in germ cell tumors
- Test: other assays for specific pathogens based on history of exposure
- Significance: For a patient with a large mass or potential cardiopulmonary compromise, goal is rapid diagnosis using least invasive/painful procedure, to minimize need for sedation/anesthesia.
- Test: pulmonary function test
- Significance: may be useful to assess pulmonary reserve
- Test: bone marrow aspiration/biopsy
- Significance: simplest procedure if CBC is suspicious
- Test: lymph node biopsy
- Significance: if adenopathy at easily accessible site
- Test: biopsy of mass
- Significance: Consider radiologically guided fine-needle biopsy.
- Test: pleurocentesis, pericardiocentesis, or excision of isolated mass
- Significance: may have both diagnostic and therapeutic roles
- Test: lumbar puncture
- Significance: may be combined with other procedures if meningitis or hematologic malignancy is suspected
Alert
Recumbent positioning, sedation, or positive pressure ventilation may lead to catastrophic respiratory or cardiovascular collapse in patients with partial compromise.
- Imaging of airway and consultation with anesthesia, surgeons, and critical care specialists should be obtained prior to any sedation.
- Procedures may need to be done with local anesthesia only with patient sitting upright.
Imaging
- Chest radiograph (lateral film required) to establish size and location of mass
- CT of the chest (if patient can tolerate semirecumbent positioning)
- To define size, location, and consistency of mass
- To assess large blood vessels and airways
- Echocardiogram to assess diastolic filling and vascular patency
Treatment
- First line
- Steroids may be given after diagnosis is established to treat hematologic malignancies or decrease edema/inflammation.
- If leukemia/lymphoma, diagnostic lumbar puncture should be performed prior to steroid treatment if possible.
- Additional therapy depends on diagnosis (e.g., chemotherapy, antibiotics).
Special Therapy
- Radiotherapy
- May be indicated for emergent management of malignancies
Additional Therapies
General Measures
- Close monitoring of cardiorespiratory status
- With cardiorespiratory compromise, avoid positive-pressure ventilation, if feasible.
- Definitive therapy will be based on the diagnosis.
Alert
- Do not treat a patient with wheezing who has no history of asthma with steroids without obtaining a chest radiograph to confirm that there is no mediastinal mass.
- If symptoms are progressing rapidly or there is evidence of superior vena cava syndrome, tracheal compression, or spinal cord compression, emergent steroids or radiation may be required, following rapid diagnostic procedures if possible.
Surgery/Other Procedures
- May be required for diagnostic biopsy
- Excision may relieve acute compression and may be primary therapy for isolated benign mass.
Ongoing Care
Admission Criteria
- All patients with significant mass, until cardiopulmonary risk defined
- All patients with evidence of significant airway or vascular compression
- All patients with evidence of significant tumor lysis syndrome
Discharge Criteria
Resolution/resection of mass, or clear evidence of cardiopulmonary stability through all activities of daily living (ADLs), including sleep
Complications
- Superior vena cava syndrome
- Tracheal compression
- Spinal cord compression
- Pleural and pericardial effusions
- Secondary infection
- Horner syndrome: ptosis, miosis, and anhydrosis resulting from compression of the cervical sympathetic nerve trunk
- Esophageal narrowing or erosion: may result in feeding difficulty or bleeding
- Tumor lysis syndrome with electrolyte disturbances, kidney failure
Additional Reading
- Franco A, Mody NS, Meza MP. Imaging evaluation of pediatric mediastinal masses. Radiol Clin North Am. 2005;43(2):325 " 353. [View Abstract]
- Gothard JW. Anesthetic considerations for patients with anterior mediastinal mass. Anesthesiol Clin. 2008;26(2):305 " 314. [View Abstract]
- Jaggers J, Balsara K. Mediastinal masses in children. Semin Thorac Cardiovasc Surg. 2004;16(3):201 " 208. [View Abstract]
- Pizzo PA, Poplack DG, eds. Principles and Practice of Pediatric Oncology. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2011.
Codes
ICD09
- 786.6 Swelling, mass, or lump in chest
- 748.8 Other specified anomalies of respiratory system
- 212.5 Benign neoplasm of mediastinum
- 164.9 Malignant neoplasm of mediastinum, part unspecified
- 748.4 Congenital cystic lung
- 239.89 Neoplasms of unspecified nature, other specified sites
- 164.8 Malignant neoplasm of other parts of mediastinum
- 164.2 Malignant neoplasm of anterior mediastinum
- 164.3 Malignant neoplasm of posterior mediastinum
- 785.6 Enlargement of lymph nodes
- 741.92 Spina bifida without mention of hydrocephalus, dorsal (thoracic) region
ICD10
- R22.2 Localized swelling, mass and lump, trunk
- Q34.1 Congenital cyst of mediastinum
- D15.2 Benign neoplasm of mediastinum
- C38.3 Malignant neoplasm of mediastinum, part unspecified
- D38.3 Neoplasm of uncertain behavior of mediastinum
- Q05.6 Thoracic spina bifida without hydrocephalus
- R59.0 Localized enlarged lymph nodes
- C38.1 Malignant neoplasm of anterior mediastinum
- Q33.0 Congenital cystic lung
- D49.89 Neoplasm of unspecified behavior of other specified sites
- C38.2 Malignant neoplasm of posterior mediastinum
SNOMED
- 94147001 mass of mediastinum (finding)
- 60652005 Congenital cyst of mediastinum (disorder)
- 92214000 Benign neoplasm of mediastinum (disorder)
- 363494000 Malignant tumor of mediastinum
- 40478000 Cyst of thymus gland (disorder)
- 164145000 On examination - lymphadenopathy (context-dependent category)
- 609302002 Pericardial cyst (disorder)
- 449224009 Malignant neoplasm of anterior mediastinum (disorder)
- 448670003 Malignant neoplasm of posterior mediastinum (disorder)
- 126725000 Neoplasm of mediastinum (disorder)
- 203981000 Thoracic spinal meningocele (disorder)
FAQ
- Q: What should be done if the child is asymptomatic and a mediastinal mass is an incidental finding on chest x-Ray?
- A: Careful history and physical with specific attention to pulmonary, cardiac, and hematologic systems.
- Vital signs to include temperature and pulse oximetry
- CBC, differential, ESR, tumor lysis labs
- PPD, anergy panel if high risk for tuberculosis or initial evaluation is negative
- CT of chest
- Referral to oncologist, surgeon, or infectious disease specialist pending above results
- Q: When should an oncologist be consulted?
- A: With any of the following:
- Rapidly enlarging mass
- Signs and symptoms of tracheal compression, superior vena cava syndrome, or spinal cord compression
- Hepatomegaly, splenomegaly, lymphadenopathy, bruises, or petechiae on physical examination
- Anemia, thrombocytopenia, or leukocytosis suggesting bone marrow involvement
- Malignant histology demonstrated with biopsy
- When help is needed in establishing diagnosis