Fibrosing mediastinitis (FM) is an uncommon diagnosis that involves the proliferation of extensive, dense fibrous tissue in the mediastinum. FM accounts for less than 1% of people with prior infection by Histoplasma capsulatum that develop hypersensitivity immune responses to antigens released during the initial exposure. Other causes include tuberculosis, blastomycosis, sarcoidosis, radiation, and idiopathic. We describe FM presenting with superior vena cava (SVC) syndrome. A 66-year-old Caucasian male presented with a one-week history of progressively worsening facial swelling associated with dysphonia, bilateral ptosis, dyspnea on exertion, and unintentional weight loss of 30 pounds within the past three months. He had a 40-pack-year smoking history and a past medical history of essential hypertension, peripheral vascular disease, and bilateral internal carotid artery stenosis. The CT chest demonstrated non-specific soft tissue extending throughout the mediastinum and towards the right hilar region, complicated by severe attenuation of the superior vena cava and a 2.4 cm × 1.6 cm necrotic lymph node. The mediastinum had hyperemic and desmoplastic changes heavily encased in venous collaterals. L4 lymph node pathological evaluation demonstrated sinus histiocytosis and reactive lymphoid hyperplasia without signs of malignancy or atypia. The patient was treated with corticosteroid and diuretic therapy to achieve intermittent symptomatic relief, but continued to decline clinically, ultimately leading to his demise. The diagnosis of FM is best obtained through CT chest with intravenous contrast to demonstrate abnormal mediastinal tissue and possible structural compromise. A biopsy of the mediastinal tissue may also help rule out malignancy. Only a few case reports have demonstrated mixed symptomatic and radiologic responses to anti-inflammatory and/or antifungal treatment. Even non-surgical and surgical interventions have shown inconsistent efficacy, with frequent restenosis warranting re-exploration.