Fibrosing Mediastinitis

#med #disease

Presentation :

Rare disorder that is characterized by aggressive fibrosis of the mediastinum leading to compression of nearby mediastinal structures:
- SVC Syndrome (develops slowly thus collateralization may occur preventing more severe symptoms, can develop/worsen acutely if thrombosis occurs)
- Obstructive Pneumonias (2/2 airway compression)
- Pulmonary vascular obstruction => pHTN (dyspnea, hypoxia, hemoptysis) + pulm infarcts
- Esophageal compression => dysphagia and/or odynophagia
Suspicion should be higher in patients who live or have previously lived in regions that are endemic for histoplasma (along the Ohio and Mississippi river valley in the central US)

Thought to be caused by pathologic immune response to infection, typically histoplasmosis or less commonly tuberculosis.
May also be idiopathic

Chest CT w/ contrast is the imaging of choice as it shows location and severity of disease, as well as any vascular/airway narrowing/obstruction, and the presence of calcification
- The characteristic CT findings consist of a dense infiltrative heterogeneous mediastinal process that obliterates fat planes, with or without a discrete mass, often with internal calcifications
- CT may also reveal evidence of prior Histoplasma infection, such as calcified lymph nodes distant from the lesion and hepatic or splenic calcifications
- Contrast ideally timed to show both pulm arterial and venous circulation
May appear on CXR as enlarged mediastinum/mediastinal lymphadenopathy
~80% of patients have unilateral disease

There is no curative therapy for fibrosing mediastinitis, only symptomatic treatments
Vascular, airway, or esophageal stents can help reduce compressive symptoms

Fibrosing mediastinitis is a chronic, progressive disease with a variable natural history.
Current therapies do not improve survival and are mostly palliative