Introduction

Fibrosing mediastinitis (FM), also known as mediastinal fibrosis or sclerosing mediastinitis, is an unprecedented, kind and dynamic condition characterized by an obtrusive multiplication of fibrous tissue inside the mediastinum. FM influences people between 13 and 65 years old and is most prevalent in females.¹

Tuberculosis and histoplasmosis are the major causes of the granulomatous form of FM, whereas non-granulomatous FM is an idiopathic response to immune system disorders, drugs (e.g. methysergide) and radiation. It is as often as possible related with other fibrosing conditions such as retroperitoneal fibrosis, essential sclerosing cholangitis, orbital pseudotumor, etc.²

Tuberculosis and histoplasmosis are major causes of the granulomatous form of FM, whereas the non-granulomatous form is an idiopathic response to immune system disorders, certain drugs (e.g. methysergide) and radiation. It is often associated with other fibrosing conditions such as retroperitoneal fibrosis, primary sclerosing cholangitis, and orbital pseudotumor.²

Symptoms of Fibrosing Mediastinitis

Symptoms may develop progressively, often presenting with worsening shortness breath and cough. Pulmonary artery occlusions can lead to pulmonary hypertension, which may result in right-sided heart failure. Patients may experience dyspnea on exertion, palpations, syncope or hemoptysis.³

When the superior vena cava SVC is involved, patients often report facial swelling, headaches and distension of the veins in the neck and/or chest wall.³ CT and MRI play a crucial role in the diagnosis and management of fibrosing mediastinitis.⁴

Surgical Interventions for Fibrosing Mediastinitis

Surgical interventions for FM are considered when medical management and less invasive methods are ineffective or when the condition leads to significant complications. The primary goals of surgery are to relieve obstructions, restore function and improve the patient’s quality of life. Given the complex anatomy and potential risks, surgical approaches are often tailored to the specific structures affected. 

Interventional procedures may be indicated in cases of compression and/or obstruction of mediastinal structures. These include percutaneous angioplasty to widen a stenosed vessel, open debulking of the mediastinal fibrous mass with or without decompression and venous grafting to alleviate superior vena cava syndrome. 

Below are a few common surgical interventions for fibrosing mediastinitis:

Excision and Drainage of Active Mediastinal Granulomas via Open Thoracotomy^5,6

This procedure is performed in patients with descending necrotizing mediastinitis (DNM), a severe infection that spreads from the cervical region to the mediastinal connective tissue. Studies have shown that patients who underwent surgery for mediastinal histoplasmosis during the acute granulomatous stage of the disease had excellent outcomes, with no progression of the infection, as evidenced by the absence of respiratory symptoms or vena cava obstruction. Early detection of the DNM, along with prompt thoracotomy and irrigation of the mediastinum and thoracic cavity is recommended to reduce mortality rates. 

Balloon angioplasty⁷

A common treatment approach for pulmonary artery stenosis in the pediatric population is percutaneous endovascular stent placement, which has been shown to effectively relieve stenosis. However, in-stent restenosis can limit its long-term efficacy. Patients with histoplasmosis-induced fibrosing mediastinitis resulting in pulmonary artery stenosis are typically treated with cutting balloon angioplasty followed by stent placement. 

Percutaneous Intravascular Stent Placement⁸

Percutaneous stent placement is considered for the treatment of superior vena cava and pulmonary artery obstruction secondary to mediastinal fibrosis (MF). This approach offers a novel therapeutic option for select MF patients who previously had no viable treatment alternatives. Vascular stents have been successfully used in other conditions affecting pulmonary veins and arteries, making them a potential option for MF patients as well. Early evidence suggests that stenting is both effective and safe, and it may provide long-term improvement in some patients. 

Catheter-Based Intervention⁹

Catheter-based interventions are considered for pulmonary valve stenosis in FM. Although this treatment improves hemodynamics, short-term vascular patency and patient symptoms, it is associated with a high rate of life-threatening complications, restenosis, and mortality. Despite these risks, catheter-based intervention remains the only palliative option available to enhance the quality of life in severely symptomatic patients with pulmonary valve stenosis and FM. 

Vascular Bypass Grafting¹⁰

Reconstruction using an autogenous spiral saphenous vein graft yields excellent clinical outcomes, with a long-term patency rate of 80%. While the superficial femoral vein is a suitable graft option, it is used less frequently due to the risk of thrombosis and distal venous insufficiency at the donor site. In comparison, prosthetic grafts have a shorter patency period and poorer clinical outcomes than autogenous grafts. 

Endvenectomy and Decompression¹¹

Endvenectomy of the superior vena cava and thrombectomy of the left vein for superior vena cava obstruction due to fibrosing calcified mediastinal histoplasmosis have proven to be effective in relieving the obstruction. These procedures should be attempted before considering graft bypass or replacement methods. Decompression of the superior vena cava through endvenectomy and thrombectomy can be easily performed if the dissection begins from the intrapericardial free portion of the superior vena cava. 

Non-Surgical Management of FM

Management of FM is dependent on the extent and severity of the disease. Below are some non-surgical interventions found to be effective for the management of FM:

• Corticosteroids and nonsteroidal anti-inflammatory drugs
• Antifungal therapy (eg, Itraconazole)¹²
• Systemic immunosuppressants¹³

Conclusion

Clinical treatment remains uncertain due to limited reports with conflicting outcomes. Despite anatomical complications, surgical treatment continues to be the primary option, although its long-term effects are still unclear. In the future, treatment may need to be tailored to the individual’s unique inflammatory and fibroproliferative response.