Sclerosing mediastinitis of unknown origin: Report of a case

Non-IgG4-Related Fibrosing Mediastinitis Diagnosed on Core Needle Biopsy and Treated with Steroids: A Case Study and Review of the Differential Diagnoses

OBJECTIVES

This study aimed to investigate the histological characteristics and treatment efficacy of non-immunoglobulin G4-related fibrosing mediastinitis and discuss differential diagnoses for this rare entity.

METHODS

We present a case study of non-immunoglobulin G4-related fibrosing mediastinitis diagnosed on core biopsy and treated with steroids. A total of four 18-gauge core needle biopsy specimens were obtained for surgical pathology. Analysis of the patient's medical history, radiological characteristics of fibrosing mediastinitis, histological features, immunohistochemistry results, the differential diagnosis and treatment efficacy of different types of fibrosing mediastinitis was performed.

RESULTS

This report describes a unique presentation of fibrosing mediastinitis (syncope and weight loss) that was concerning for malignancy. Histological, laboratory and radiographical studies confirmed the diagnosis of non-immunoglobulin G4-related fibrosing mediastinitis. The patient received corticosteroid treatment which showed marked improvement after 1 month of treatment.

CONCLUSIONS

Fibrosing mediastinitis is an extremely uncommon entity with unknown pathogenesis, and it is more important to rule out malignancy and infection than to delineate between fibrosing mediastinitis and IgG4-related disease. In doing this, we may reasonably initiate a trial of corticosteroids which may prove beneficial, as in this patient. More studies on the pathogenesis of fibrosing mediastinitis are necessary to guide better directed treatments.

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.

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.

Thymic inflammatory pseudotumor with multilocular thymic cyst caused by immunoglobulin G4-related disease

A 44-year-old man was referred to our hospital after an anterior mediastinal tumor was noted on computed tomography during follow-up observation after left testicular seminoma resection. Chest computed tomography revealed an enhanced mass measuring 33 x 16 x 15 mm at the anterior mediastinum. Chest magnetic resonance imaging revealed high signal intensity on T2-weighted imaging, and F¹⁸  fluorodeoxyglucose-positron emission tomography showed a maximum standardized uptake of 12.45. Laboratory tests revealed no elevated tumor markers, except for mildly elevated interleukin-2. Based on these results, complete resection was performed under suspicion of a malignant tumor, mediastinal metastasis of seminoma, or malignant lymphoma. An extended thymectomy with partial merger pericardial resection was performed using a subxiphoid approach. Small nodules and multiple thymic cysts were observed the thymus in addition to the main mass. Microscopic examination of the tumor revealed fibrosis, lymphocyte infiltration with lymphoid follicular hyperplasia, and hyperplasia of the thymus. Numerous immunoglobulin G4 (IgG4)-positive plasma cells were found on immunohistochemical staining. The ratio of IgG4 to total IgG was approximately 60%. We ultimately diagnosed the patient with a thymic inflammatory pseudotumor with multilocular cyst caused by IgG4-related disease.

Fibrosing mediastinitis: a rare complication of histoplasmosis

We report a case of a 29-year-old man who presented with intermittent haemoptysis for about 18 months. Previously, his symptoms had been diagnosed as musculoskeletal pain and later as pneumonia. CT found a venous infarct in the right lung in addition to extensive lymphadenopathy in the mediastinum and pulmonary hila, with associated calcifications almost completely occluding the superior vena cava and azygos vein. Further questioning revealed that the patient had once worked on an organic farm in Colorado. Subsequent work up was positive for histoplasmosis yeast antibodies. The patient was diagnosed with fibrosing mediastinitis (FM) and started on itraconazole for 3 months. We note that FM is a rare complication of histoplasmosis and can present as chronic haemoptysis. Travel history is an important aspect of the clinical evaluation. Antifungal agents have shown some efficacy in treating histoplasmosis-related FM.