Which are the causes of Fibrosing Mediastinitis?

Fibrosing mediastinitis is a rare condition characterized by the excessive growth of fibrous tissue in the mediastinum, the central compartment of the chest that contains the heart, major blood vessels, esophagus, trachea, and other vital structures. This abnormal fibrous tissue growth can lead to compression and obstruction of these structures, causing various symptoms and complications.

The exact cause of fibrosing mediastinitis is not fully understood, but it is believed to be primarily associated with two main factors:

1. Histoplasmosis infection:

Histoplasmosis is a fungal infection caused by inhaling spores of the fungus Histoplasma capsulatum, which is commonly found in soil contaminated with bird or bat droppings. Most people who are exposed to the fungus do not develop any symptoms or experience only mild flu-like symptoms. However, in some individuals, the infection can progress and lead to fibrosing mediastinitis.

When the body's immune system responds to the histoplasmosis infection, it triggers an inflammatory reaction. In some cases, this immune response can be excessive, leading to the formation of granulomas (small nodules) in the affected tissues. Over time, these granulomas can undergo fibrosis, resulting in the development of fibrosing mediastinitis.

2. Autoimmune response:

Another potential cause of fibrosing mediastinitis is an autoimmune response. Autoimmune diseases occur when the immune system mistakenly attacks healthy tissues in the body. In the case of fibrosing mediastinitis, it is hypothesized that an autoimmune reaction may trigger the excessive growth of fibrous tissue in the mediastinum.

Although the exact mechanisms underlying this autoimmune response are not fully understood, it is believed that certain genetic and environmental factors may play a role. Genetic predisposition, exposure to certain toxins or infections, and other unknown triggers may contribute to the development of an autoimmune reaction in susceptible individuals.

Other potential factors:

While histoplasmosis infection and autoimmune response are considered the primary causes of fibrosing mediastinitis, there are other potential factors that may contribute to its development:

• Other infections: Besides histoplasmosis, other infections such as tuberculosis, syphilis, or fungal infections can also lead to fibrosing mediastinitis, although they are less common causes.


• Environmental exposure: Exposure to certain environmental toxins or irritants may increase the risk of developing fibrosing mediastinitis. However, specific substances or triggers have not been definitively identified.


• Genetic factors: There may be a genetic predisposition to developing fibrosing mediastinitis, as some cases have been reported in families. However, the specific genes involved and the inheritance pattern are not yet fully understood.


• Immune system dysfunction: Individuals with underlying immune system disorders or weakened immune systems may be more susceptible to developing fibrosing mediastinitis.

It is important to note that fibrosing mediastinitis is a rare condition, and not everyone who experiences histoplasmosis infection or autoimmune response will develop this complication. The exact reasons why some individuals develop fibrosing mediastinitis while others do not remain unclear and require further research.