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.
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.
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
- mediastinal lymphoma
- Kaposi sarcoma
- certain non-lymphomatous pulmonary lymphoid disorders
- infective etiology
- occupational lung disease
- mediastinal lymphadenopathy in interstitial lung disease
- pulmonary manifestation of rheumatoid arthritis (rare) 5
- scleroderma / CREST syndrome 10,11
- related to congestive cardiac failure 7,8
- medication-related, e.g. phenytoin, methotrexate 6
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 9. Interval size increase on follow up dictates the need for biopsy.
- 1. Goldberg SN, Raptopoulos V, Boiselle PM et-al. Mediastinal lymphadenopathy: diagnostic yield of transbronchial mediastinal lymph node biopsy with CT fluoroscopic guidance-initial experience. Radiology. 2000;216 (3): 764-7. doi:10.1148/radiology.216.3.r00se32764 - Pubmed citation
- 2. Boiselle PM, Patz EF, Vining DJ et-al. Imaging of mediastinal lymph nodes: CT, MR, and FDG PET. Radiographics. 1998;18 (5): 1061-9. doi:10.1148/radiographics.18.5.9747607 - Pubmed citation
- 3. Suwatanapongched T, Gierada DS. CT of thoracic lymph nodes. Part II: diseases and pitfalls. Br J Radiol. 2006;79 (948): 999-1000. doi:10.1259/bjr/82484604 - Pubmed citation
- 4. Kumar A, Dutta R, Kannan U et-al. Evaluation of mediastinal lymph nodes using F-FDG PET-CT scan and its histopathologic correlation. Ann Thorac Med. 2011;6 (1): 11-6. doi:10.4103/1817-1737.74270 - Free text at pubmed - Pubmed citation
- 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
- 9. Munden RF, Carter BW, Chiles C, MacMahon H, Black WC, Ko JP, McAdams HP, Rossi SE, Leung AN, Boiselle PM, Kent MS, Brown K, Dyer DS, Hartman TE, Goodman EM, Naidich DP, Kazerooni EA, Berland LL, Pandharipande PV. Managing Incidental Findings on Thoracic CT: Mediastinal and Cardiovascular Findings. A White Paper of the ACR Incidental Findings Committee. (2018) Journal of the American College of Radiology : JACR. 15 (8): 1087-1096. doi:10.1016/j.jacr.2018.04.029 - Pubmed
- 10. Bhalla M, Silver RM, Shepard JA, McLoud TC. Chest CT in patients with scleroderma: prevalence of asymptomatic esophageal dilatation and mediastinal lymphadenopathy. (1993) AJR. American journal of roentgenology. 161 (2): 269-72. doi:10.2214/ajr.161.2.8333359 - Pubmed
- 11. Farrokh D, Abbasi B, Fallah-Rastegar Y, Mirfeizi Z. The Extrapulmonary Manifestations of Systemic Sclerosis on Chest High Resolution Computed Tomography. (2015) Tanaffos. 14 (3): 193-200. Pubmed