Description

• Partial or complete obstruction of the superior vena cava (SVC) (1):
  • ~60% due to malignant causes
  • 20–40% thrombosis or nonmalignant causes
• Usual course: acute; usually 2 to 4 weeks from onset of symptoms to diagnosis
• Synonym(s): superior mediastinal syndrome; SVC obstruction

Epidemiology

• Predominant age: all ages, less commonly children and young adults (16 to 30 years)
• Predominant sex: male > female

Incidence
15,000 new cases per year in the United States (1)

Etiology and Pathophysiology

Obstruction of the SVC causes increased pressure of the venous system responsible for draining the upper chest and neck. This obstruction causes retrograde collateral flow and interstitial edema, which may result in the rapid development of cerebral edema, intracranial thrombosis, and death.

• Malignancy
  • In adults, obstruction may be related to a primary tumor or lymph node metastasis (1).
    • Non–small cell lung cancer
    • Small cell lung cancer
    • Lymphoma
    • Metastatic lesions (most commonly from breast and testicular cancers)
• Infections
• Iatrogenic intravascular devices
• Thyroid goiter
• Thrombosis of SVC
• Pericardial constriction
• Idiopathic sclerosing mediastinitis
• Aortic aneurysm
• In children, most common after cardiac surgical procedures

Risk Factors

• Uncontrolled primary cancer
• History of mediastinal tumor
• Previous invasive procedures
• Intravascular devices

General Prevention

No preventive measures known

Commonly Associated Conditions

• Malignancy:
  • Common: lung, lymphoma, and metastatic breast
  • Less common: germ cell tumors, thymoma, and mesothelioma
• Hyperthyroidism
• Infections: tuberculosis, histoplasmosis, syphilis