Idiopathic Mediastinal Fibrosis: a Systemic Immune-Mediated Disorder. A Case Series and a Review of the Literature

CT and 18FDG-PET/CT findings in progressive mediastinal idiopathic fibrosis as a benign mimicker of esophageal carcinoma: a case report

Idiopathic mediastinal fibrosis, also called sclerosing or fibrosing mediastinitis, is a very rare and aggressive fibroinflammatory process characterized by fibrous tissue proliferation in the mediastinal region. Herein, we present a rare case of idiopathic mediastinal fibrosis presenting with esophageal obstruction, most likely associated with immunoglobulin G (IgG4)-related disease, affecting the posterior mediastinum with intrapulmonary infiltration. Computed tomography revealed a narrowed lumen and thickened wall of the distal esophagus surrounded by a necrotic mass with infiltration into the nearby structures, suggesting a locally advanced malignant process. Positron emission tomography revealed intense accumulation of 18F-fluorodeoxyglucose, indicating an active inflammatory component, which complicates further differential diagnosis of mediastinal masses. Thoracoscopic biopsy and immunohistochemical analysis confirmed a fibroinflammatory process with perivascular lymphoid cell infiltration that was cluster of differentiation (CD)3 (++) and CD20 (++), with massive numbers of IgG4-immunoreactive plasma cells. Although a benign condition, sclerosing mediastinitis is a close mimicker of esophageal carcinoma, which cannot be differentiated by computed tomography or positron emission tomography and must be considered in a differential diagnosis.

Unexpected fibrous mediastinitis in a patient with myasthenia gravis - a case report

BACKGROUND

Fibrous mediastinitis (FM) is a rare mediastinal lesion characterized by proliferation of fibrous tissue within the mediastinum. Previous reports have shown that this lesion can be caused by histoplasmosis and tuberculosis. In extremely rare cases, FM can also be caused by autoimmune diseases such as antineutrophil cytoplasmic antibody-associated vasculitis and large-vessel arteritis.

CASE PRESENTATION

In our case, we report unexpected fibrous mediastinitis found after robotic thymectomy in a patient with myasthenia gravis (MG). The preoperative imaging indicated no obvious lesion in the mediastinum and the patient denied histories of both histoplasmosis and tuberculosis. After the operation, both proliferation of fibrous tissue and ectopic germinal centres (GCs) could be found in the thymus.

CONCLUSION

This rare case might enrich our knowledge of the relationship between FM and autoimmune diseases.

Idiopathic fibrosing mediastinitis with esophageal varices: A case report

Fibrosing mediastinitis (FM) is a rare cause of lung fibrosis with multiple etiologies ranging from infectious to autoimmune to idiopathic. Common causes of FM include histoplasmosis and a relatively new cause of IgG4-related disease. We present a 55-year-old male with symptoms of esophageal varices, intractable hiccups, and progressive difficulty in breathing. A chest X-ray showed right lung fibrosis with pleural effusion and loss of lung volume, which was originally thought to be the sequelae of SARS-CoV-2 or metastasis, but computed tomography of the chest revealed FM. His variceal bleeding was controlled, and he was discharged home. However, treatment for FM was not pursued because the cause was not identified. Using corticosteroids may not cease the progression of the disease, and surgical options are available when symptoms persist. Idiopathic FM requires laboratory and radiological findings to exclude relevant differential diagnoses.

Pulmonary Hypertension Caused by Fibrosing Mediastinitis

Pulmonary hypertension (PH) is a progressive and severe disorder in pulmonary hemodynamics. PH can be fatal if not well managed. Fibrosing mediastinitis (FM) is a rare and benign fibroproliferative disease in the mediastinum, which may lead to pulmonary vessel compression and PH. PH caused by FM (PH-FM) is a pathologic condition belonging to group 5 in the World Health Organization PH classification. PH-FM has a poor prognosis because of a lack of effective therapeutic modalities and inappropriate diagnosis. With the development of percutaneous pulmonary vascular interventional therapy, the prognosis of PH-FM has been greatly improved in recent years. This article provides a comprehensive review on the epidemiology, pathophysiologic characteristics, clinical manifestations, diagnostic approaches, and treatment modalities of PH-FM based on data from published reports and our medical center with the goal of facilitating the diagnosis and treatment of this fatal disease.

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PH-FM, as a type of rare condition in group 5 PH, has a poor prognosis because of a lack of effective therapeutic modalities and frequent misdiagnosis and underdiagnosis.

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The most prevalent trigger of FM is H-FM in the United States and TB-FM in China.

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Imaging findings, including mismatched perfusion defects in the V/Q scan, FM dyad, and FM triad are important diagnostic clues, and clinical classification facilitates decision making in diagnosis and therapeutics.

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Because of the limited efficacy of drug therapy as well as the uncertain effectiveness and high risk of surgical treatment, endovascular interventional modality is currently the preferred therapeutic option, although procedure-related complications and intrastent restenosis after PV intervention need to be addressed.

IgG4 ‐associated fibrosing mediastinitis requiring differentiation from posterior mediastinal tumour: A case report

A 71‐year‐old man, who was found to have a posterior mediastinal tumour, was referred to our hospital. Contrast‐enhanced computed tomography (CT) showed a 15‐cm soft tissue shadow in the posterior mediastinum, with many affected areas and a gradually increasing pattern. We also detected oligemic areas with poor contrast‐filling. There was no invasion into the adjacent vertebral body and the blood vessels penetrating the interior were intact. Positron emission tomography–CT revealed a high maximum standardized uptake level of 4.53 in the mediastinal masses. We performed thoracoscopic surgery for the biopsy. Histological findings showed lymphoplasmacytic infiltration in the fibrous stroma as well as storiform fibrosis. Immunohistochemical examination revealed abundant infiltration of immunoglobulin G4 (IgG4)‐positive plasma cells and 40% IgG4/IgG‐positive plasma cells. Postoperative serum examinations showed a high serum IgG4 level (570 mg/dl). Accordingly, we diagnosed the patient with IgG4‐related fibrosing mediastinitis, a rare manifestation of IgG4‐related disease.

Clinical Features of Fibrosing Mediastinitis in Japanese Patients: Two Case Reports and a Literature Review

Fibrosing mediastinitis (FM) is a rare fibroinflammatory disease of the mediastinum with an etiology and clinical features that vary by world region. The characteristics of FM in Japan are still unknown. We herein report two Japanese patients with FM who were treated with corticosteroids and responded well. We also reviewed the Japanese literature on PubMed® and summarized the characteristics of 27 Japanese FM patients, including our two patients. In Japan, the predominant cases were those without a specific cause, were diffusely distributed, and responded well to corticosteroid therapy.

Idiopathic fibrosing mediastinitis

Fibrosing mediastinitis is rare in settings where histoplasmosis is not endemic. An idiopathic form of the disease may present with indistinguishable features and requires methodical exclusion of competing differential diagnoses. We report the case of a 30-year old female patient who presented with intermittent haemoptysis for the past 2 years with no constitutional symptoms. Computed tomography of the chest revealed a prominent right bronchial arterial circulation with a mass-like lesion, which encased and attenuated the right pulmonary trunk and adjacent structures. Endobronchial ultrasonography with transbronchial fine-needle aspiration showed a paucicellular aspirate with no evidence of malignancy or granulomas. Fungal infection, tuberculosis, sarcoidosis, IgG4-disease, and connective tissue disease were ruled out by appropriate serological, molecular, and microbiological tests. A diagnosis of idiopathic fibrosing mediastinitis was therefore made by exclusion and the patient was successfully treated with oral corticosteroids.

Thoracic paravertebral involvement in patients with IgG4-related disease: CT and MR imaging findings

OBJECTIVES

To retrospectively evaluate CT and magnetic resonance (MR) imaging thoracic paravertebral findings at baseline and follow-up in patients with IgG4-related disease.

METHODS

The study consisted of 36 patients with IgG4-related disease involving thoracic paravertebral regions (32 men and four women; mean age, 58 years; range, 25-78 years). A total of 36 patients underwent CT or MR imaging at baseline; 20 patients underwent follow-up. CT and MR images were reviewed and analysed in consensus by two radiologists for the various features of thoracic paravertebral lesions.

RESULTS

All lesions were located around two or more thoracic vertebrae, particularly the lower thoracic vertebrae (n = 36). The right side of vertebrae was predominantly affected in all cases (n = 36). Radiologically, IgG4-related thoracic paravertebral lesions were categorized into three types: solitary or multiple saddle-like masses type (32 patients); multiple nodules type (three patients); and invasively irregular mass type (three patients). All the types showed soft-tissue density on CT images, isointense on T1- and T2-weighted images, and homogeneous enhancement with penetration of small arteries in the lesions on contrast-enhanced CT and MR images. Steroid therapy administered to 20 patients dramatically diminished the mean maximum thickness in 18 patients. One patient with T7-12 vertebrae involved improved after steroid therapy.

CONCLUSION

IgG4-related paravertebral lesions occur mainly around the right side of the lower thoracic vertebrae and manifest as three major patterns of CT and MR imaging findings. Recognition of these diagnostic features will assist in the diagnosis and treatment of IgG4-related disease.

Ptosis and Miosis Associated with Fibrosing Mediastinitis

BACKGROUND Fibrosing mediastinitis is a rarely seen, progressive disease. It results from an excessive fibrotic reaction in the mediastinum. We describe a presentation of fibrosing mediastinitis that, to our knowledge, has never been seen before. CASE REPORT A 30-year-old female Colombian flight attendant presented with a right eyelid droop. Examination revealed partial right-sided ptosis and miosis but no anhidrosis. An ill-defined firm swelling was palpable at the root of the neck. Chest radiography revealed a widened mediastinum, and computerized tomography (CT) showed a right paratracheal mass without calcification extending to the thoracic inlet, encasing multiple blood vessels. All basic blood tests, magnetic resonance imaging of the head, and ultrasound Doppler of the neck vessels were normal. History and work up for infections including fungal diseases, granulomatous diseases, vasculitis, and autoimmune diseases were negative. Positron emission tomography (PET) showed significant FDG uptake in the mediastinum. Mediastinal biopsy was histologically consistent with fibrosing mediastinitis. All relevant immunohistochemistry and microbiological studies were negative. Subsequently, the patient developed signs of superior vena cava compression; this was managed by balloon angioplasty, which resulted in improvement of symptoms. However, over time, her symptoms worsened progressively, resulting in a left-sided ptosis and radiological progression of the mass on CT. She received treatment with rituximab and concomitant steroids, which yielded excellent results: the treatment led to both resolution of her symptoms and regression of the mass and its metabolic activity on PET scan. CONCLUSIONS Fibrosing mediastinitis can present with an incomplete Horner's syndrome. Treatment with rituximab and steroids shows promising results in select cases of metabolically active idiopathic fibrosing mediastinitis.

IgG4-related disease: a clinical perspective

IgG4-related disease (IgG4-RD) is a recently recognized fibro-inflammatory disorder that can affect almost any organ. Common presentations include major salivary and lacrimal gland enlargement, orbital disease, autoimmune pancreatitis, retroperitoneal fibrosis and tubulointerstitial nephritis. The main histopathological features are a dense, polyclonal, lymphoplasmacytic infiltrate rich in IgG4+ plasma cells, storiform fibrosis and obliterative phlebitis. The precise pathogenic mechanisms of IgG4-RD are still unclear. CD4+ T and B cells, including IgG4-expressing plasmablasts, constitute the major inflammatory cell populations and are believed to cause organ damage and tissue fibrosis. The diagnosis of the disease may be challenging and should be based on specific histopathological findings, typical laboratory and radiological aspects and an appropriate clinical context. The first-line treatment of IgG4-RD is based on glucocorticoids, which are usually efficacious. However, B cell depletion induced by rituximab has also been found to induce remission in steroid-resistant disease or has been used as steroid-sparing agent for relapsing disease. This review provides an update on clinical and therapeutic aspects of IgG4-RD.

Successful management of fibrosing mediastinitis with severe vascular compromise: Report of two cases and literature review

Fibrosing mediastinitis is a rare disorder characterized by the invasive proliferation of fibrous tissue within the mediastinum. This fibrosis can result in compression of intrathoracic structures including the pulmonary vasculature leading to clinical symptoms and complications like pulmonary hypertension. Here, we present two cases of young patients with fibrosing mediastinitis complicated by pulmonary artery stenosis requiring medical and endovascular management with excellent results.

A review of endovascular stenting for superior vena cava syndrome in fibrosing mediastinitis

Fibrosing mediastinitis (FM) is a rare disorder of inflammation and fibrosis involving the mediastinum. The formation of fibroinflammatory mass in the mediastinum can lead to obstruction of mediastinal structures and cause severe debilitating and life-threatening symptoms. Superior vena cava syndrome (SVCS) is a dreaded complication of FM with no medical therapy proven to be efficacious. Spiral vein grafting has long been utilized as first-line therapy for SVC syndrome due to FM. Endovascular repair with stents and angioplasty for malignant causes of SVC syndrome is well established. However, there are limited data on their utility in SVC syndrome due to FM. We present two cases of SVC syndrome due to FM treated with endovascular stenting and a detailed review of current literature on its utility in SVCS due to benign causes.

Fibrosing/Sclerosing Lesions of the Mediastinum: A Review

Fibrosing lesions of the mediastinum represent a small but challenging group of lesions that range in etiology from infectious to idiopathic to neoplastic. The diagnosis of such lesions becomes more challenging in the setting of mediastinoscopic biopsies. In addition, over the years, there has been further accumulation of knowledge of the clinical aspects of these lesions that needs to be incorporated into their evaluation. Therefore, it is essential that in the general evaluation of these fibrosing processes, one not only carefully examines the histopathologic features of the lesion, that of a fibroinflammatory process with the appropriate histochemical and immunohistochemical studies, but also carefully evaluates the clinical presentation and imaging findings. Needless to say, as will be illustrated in this review, determining a definitive unequivocal diagnosis on a small mediastinoscopic biopsy may be difficult, and often one needs to provide guidance on the perspective of the histologic features present. In some cases, mainly tumoral conditions with extensive fibrosis, a conclusive diagnosis can be made; however, it is those cases in which the extensive fibrosis is the only histopathologic feature where more appropriate guidance is required. While this review will focus more on the non-neoplastic fibroinflammatory lesions of the mediastinum, within the discussion of differential diagnoses, we will discuss some neoplastic conditions that commonly show extensive fibrosing features.

Pulmonary vascular involvement of IgG4-related disease: Case series with a PRISMA-compliant systemic review

BACKGROUND

Immunoglobulin G4-related disease (IgG4-RD) is a recently recognized, immune-mediated chronic fibrotic inflammation that can involve almost all organs, causing tumefaction and dysfunction. Its presence in pulmonary circulation is underestimated and has not yet been investigated.

OBJECTIVES

We describe a representative IgG4-RD patient with pulmonary artery stenosis and pulmonary embolism, leading to reversible pulmonary hypertension. Literature review of IgG4-RD with pulmonary circulation involvement was conducted.

DATA SOURCES

References for this review were identified through searches via PubMed, EBSCO, and Web of Science for published articles before November 2016.

RESULTS

There were 15 published cases of IgG4-RD with pulmonary vascular involvement, 3 with pulmonary arteritis, 2 with pulmonary artery aneurysm, 3 with pulmonary artery stenosis, 1 with obliterative phlebitis, and 1 with pulmonary embolism. Possible immunity and inflammation mechanisms were summarized.

CONCLUSIONS

IgG4-RD with pulmonary vascular involvement is rare. Echocardiogram and contrast-enhanced chest CT are helpful to screen the disease. Clinical manifestations were found from asymptomatic to dyspnea or even syncope. And nearly all cases had more than 1 organ affected, with significantly increased serum IgG4 levels. PET/CT aided in identifying affected organs and determining candidate biopsy sites. More awareness is urged to evaluate the pulmonary vascular manifestations of this disease.

IgG4-related fibrosing mediastinitis diagnosed with computed tomography-guided percutaneous needle biopsy: Two case reports and a review of the literature

RATIONALE

Immunoglobulin G4-related disease (IgG4-RD) is a fibroinflammatory disease characterized by elevated serum IgG4 levels with infiltration of IgG4+ plasma cells and severe fibrosis in affected tissues. Recently, idiopathic fibrosing mediastinitis (FM), an extremely rare fibroinflammatory disorder, has been recognized as a form of IgG4-RD. As IgG4-RD can be treated by glucocorticoids, identification of the etiology of FM by surgical biopsy is essential; however, mediastinal biopsy is often difficult. We report 2 cases of IgG4-related FM successfully diagnosed with computed tomography (CT)-guided percutaneous needle biopsy.

PATIENT CONCERNS

Case 1 was a 66-year-old woman with elevated serum C-reactive protein without any symptoms and case 2 was 78-year-old woman with abnormal mediastinal contour on chest x-ray. By further work-up, both cases were found to have mediastinitis accompanied by elevated serum IgG4. CT-guided percutaneous needle biopsy revealed massive infiltration of IgG4+plasma cells along with storiform fibrosis.

DIAGNOSIS

IgG4-related FM.

INTERVENTIONS

Glucocorticoid therapy.

OUTCOME

The treatment resulted in significant improvement of the lesions after 3 months.

LESSONS

Early recognition and diagnosis of IgG4-related FM is essential because a delay in appropriate treatment initiation leads to progressive fibrosis with irreversible organ damage and poor prognosis. Our cases highlight CT-guided percutaneous needle biopsy as a promising option for histological examination in patients with IgG4-related FM.

Pulmonary Artery Occlusion and Mediastinal Fibrosis in a Patient on Dopamine Agonist Treatment for Hyperprolactinemia

Unusual forms of pulmonary hypertension include pulmonary hypertension related to mediastinal fibrosis and the use of serotonergic drugs. Here, we describe a patient with diffuse mediastinal fibrosis and pulmonary hypertension while she was on dopamine agonist therapy. A young woman, who was treated with cabergoline and bromocriptine for hyperprolactinemia, presented with progressive dyspnea over several months. Based on the clinical investigation results, in particular, elevated pulmonary arterial pressures and significant perfusion defects on computed tomography (CT) pulmonary angiography and ventilation/perfusion (V/Q) scintigraphy, chronic thromboembolic pulmonary hypertension (CTEPH) was initially considered the most plausible diagnosis. However, during an attempted pulmonary endarterectomy, loose fibrous tissues were observed in the mediastinum and cryosection of the right pulmonary artery showed fibrosis and chronic inflammation. Subsequent investigations revealed that diffuse mediastinal fibrosis with concurrent pulmonary hypertension, and not CTEPH, was the most likely diagnosis and cabergoline and bromocriptine may have triggered the fibrotic changes. Both drugs are ergot-derived dopamine agonists, which are known to cause cardiac valve fibrosis and less frequently, non-cardiac fibrotic changes. The underlying mechanism is attributed to their interactions with serotonin receptors. There is much evidence that serotonin, a potent vasoconstrictor and mitogen, is involved in the pathogenesis of pulmonary hypertension. In conclusion, as CT and V/Q scintigraphy findings can occasionally be deceptive, physicians should be particularly aware of differential diagnoses in patients without obvious history of venous thromboembolism that are suspected of having chronic thromboembolic pulmonary hypertension.

Sclerosing Mediastinitis Presenting as Complete Heart Block

Sclerosing Mediastinitis (SM) is a rare condition which is characterized by the presence of dense fibrosis which infiltrates and encroaches upon various structures in the mediastinal cavity. Depending on the extent and the predominant organ of involvement, the patient presents with symptomatology of dysphagia, superior vena cava compression syndrome or dyspnoea. However, the involvement of the heart is rarely seen. Aetiologies of SM are several, with infections being the most common. We discuss a case of SM involving the oesophagus, descending aorta, hilum of lungs and the heart secondary to mucormycosis in an immunocompetent male.

Idiopathic retroperitoneal fibrosis and its overlap with IgG4-related disease

Retroperitoneal fibrosis (RPF) is a rare disease characterised by fibrous tissue proliferation in the retroperitoneum, with encasement of the ureters and large vessels of the abdomen as the most destructive of potentially severe complications. It can either be idiopathic, or secondary to infections, malignancies, or the use of certain drugs. The idiopathic form accounts for approximately 75% of the cases, and is usually responsive to immunosuppressive therapy. In recent years, the emergence of a new clinical entity, IgG4-related disease (IgG4-RD), shed light on many fibro-inflammatory disorders once thought to be separate clinical entities, although frequently associated in the so-called multifocal fibrosclerosis. Among these, together with sclerosing pancreatitis and cholangitis, pseudotumour of the orbit, idiopathic mediastinal fibrosis and other conditions, is idiopathic retroperitoneal fibrosis (IRF). Both IRF and IgG4-RD can be associated with a wide variety of disorders, usually governed by immune-mediated (and particularly auto-immune) mechanisms. In our review, we discuss the clinical and therapeutic challenges IRF presents to the internist, as well as the meaning of its recent inclusion in the IgG4-RD spectrum from a clinical practice standpoint.