mediastinal lymph node enlargement

Mediastinal lymph node enlargement can occur from a wide range of pathologies, either by its own or in association with other lung pathology. Historically, a size cut-off of 10 mm short-axis diameter was used.

Terminology

Although mediastinal lymphadenopathy is used interchangeably - by some - with "mediastinal lymph node enlargement", they are not synonymous entities, and it is important to be cognizant of this. Many enlarged mediastinal nodes will be pathological, however not all, and conversely, some mediastinal lymphadenopathy will be found in non-enlarged nodes.

The diagnostic waters are muddied further as some pathologies produce nodal enlargement via reactive change, and not because the pathology is actually infiltrating the node itself, eg. bacterial pneumonia is associated with reactive enlargement of the mediastinal nodes, but the organism is not generally infecting the node itself. In tuberculosis, however, the mycobacterium is actually infiltrating and infecting the lymph node.

Some radiologists make a point of differentiating between reactive nodal enlargement and pathological nodal enlargement, reserving lymphadenopathy for the latter etiologies only.

Pathology

The spectrum of conditions that can result in mediastinal lymphadenopathy is extremely diverse and includes:

• sarcoidosis (see: pulmonary manifestations of sarcoidosis)
• primary lung cancer
• metastatic malignancies to the mediastinum from other sites
  • common
    • esophageal cancer
    • breast cancer
    • thyroid cancer
  • less common
    • malignant pleural mesothelioma
    • thymic epithelial tumor
• mediastinal lymphoma
  • primary mediastinal large B-cell lymphoma
• Kaposi sarcoma
• certain non-lymphomatous pulmonary lymphoid disorders
  • Castleman disease
  • lymphomatoid granulomatosis - pulmonary manifestations of lymphomatoid granulomatosis
  • angioimmunoblastic lymphadenopathy (AILD)
• infective etiology
  • pulmonary infection, e.g. pneumonia, pulmonary tuberculosis
  • thoracic histoplasmosis
• occupational lung disease
  • silicosis
  • coal worker's pneumoconiosis
  • chronic beryllium lung disease / 
• mediastinal lymphadenopathy in interstitial lung disease
• pulmonary manifestation of rheumatoid arthritis (rare)
• scleroderma / CREST syndrome 
• related to congestive cardiac failure
• thoracic amyloidosis
• medication-related, e.g. phenytoin, methotrexate

Practical points

If incidentally detected, the ACR committee white paper in 2018 suggests clinical consultation, further workup with CT-PET +/- follow up CT chest in 3-6 months if short-axis diameter over 15 mm and if there is no explicable disease . Interval size increase on follow up dictates the need for biopsy.

See also

• lymph node enlargement
• high attenuating lymphadenopathy
• bilateral hilar lymphadenopathy
• calcified mediastinal nodes

Siehe auch:

• Lymphadenopathie
• mediastinale Raumforderungen
• pericardial sleeve recess
• Doughnut Zeichen Thorax

und weiter:

• Heiserkeit
• Mediastinalverbreiterung