Mediastinal lymph node enlargement can occur from a wide range of pathologies. It may occur on its own or in association with other lung pathology.
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 e.g. bacterial pneumonia is associated with reactive enlargement of the mediastinal nodes, but the organism is not generally infecting the node itself, cf. tuberculosis, whereby 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 aetiologies only.
The spectrum of conditions than 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
- mediastinal lymphoma
- Kaposi sarcoma
- certain non-lymphomatous pulmonary lymphoid disorders
- infective aetiology
- occupational lung disease
- mediastinal lymphadenopathy in interstitial lung disease
- pulmonary manifestation of rheumatoid arthritis (rare) 5
- related to congestive cardiac failure 7,8
- medication-related, e.g. phenytoin, methotrexate 6
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- 5. Martinez FJ, Karlinsky JB, Gale ME et-al. Intrathoracic lymphadenopathy. A rare manifestation of rheumatoid pulmonary disease. Chest. 1990;97 (4): 1010-2. Pubmed citation
- 6. Hansell DM, Lynch DA, McAdams HP et-al. Imaging of Diseases of the Chest. Mosby. ISBN:B0054JE9QI. Read it at Google Books - Find it at Amazon
- 7. Chabbert V, Canevet G, Baixas C, Galinier M, Deken V, Duhamel A, Otal P, Joffre F, Remy J, Remy-Jardin M. Mediastinal lymphadenopathy in congestive heart failure: a sequential CT evaluation with clinical and echocardiographic correlations. (2004) European radiology. 14 (5): 881-9. doi:10.1007/s00330-003-2168-1 - Pubmed
- 8. Ngom A, Dumont P, Diot P, Lemarié E. Benign mediastinal lymphadenopathy in congestive heart failure. (2001) Chest. 119 (2): 653-6. Pubmed