Fibrosing mediastinitis causing superior vena cava syndrome in an Indian woman: a case report with 44-month follow-up

Background Fibrosing mediastinitis (FM) is a rare fibroinflammatory disorder characterized by proliferation of dense fibrous tissue within the mediastinum, with encasement and compression of adjacent structures. Superior vena cava (SVC) syndrome is an uncommon but clinically important complication. Establishing the underlying etiology may be difficult when adequate tissue cannot be obtained. We describe a case of radiologically diagnosed FM with probable tuberculosis association presenting as SVC syndrome and showing sustained clinical and imaging improvement after combined empirical antituberculosis therapy (ATT) and corticosteroids. Case presentation A 69-year-old Indian woman presented with progressive facial puffiness, exertional dyspnoea, subjective weight loss, hoarseness, and dysphagia for one and a half months. Examination revealed markedly elevated, non-pulsatile jugular venous pressure, suggesting SVC obstruction. Contrast-enhanced computed tomography of the thorax demonstrated an ill-defined infiltrative soft-tissue lesion encasing the SVC and distal left brachiocephalic vein, causing more than 80% luminal narrowing. Whole-body fluorodeoxyglucose positron emission tomography/computed tomography demonstrated metabolically active mediastinal soft tissue with a maximum standardized uptake value of 7.19. The tuberculin skin test and interferon-gamma release assay were positive. Serum angiotensin-converting enzyme and IgG4 concentrations were within normal reference ranges. Endobronchial ultrasound-guided aspiration yielded insufficient tissue for definitive histopathological diagnosis. Following multidisciplinary assessment, empirical ATT and oral prednisolone were initiated. Facial oedema and elevated jugular venous pressure improved within three months. ATT was continued for nine months, while corticosteroids were gradually tapered over an extended period. At approximately 44 months, repeat imaging demonstrated marked regression of the mediastinal soft tissue, resolution of SVC narrowing, and complete disappearance of abnormal metabolic activity. Conclusion FM should be considered in patients with non-malignant SVC syndrome. When histological confirmation is unobtainable, management may be guided by epidemiological, clinical, and imaging findings following multidisciplinary assessment. Although our patient showed sustained improvement after combined ATT and corticosteroids, the underlying aetiology and individual contribution of each treatment remain uncertain.