Superior vena cava syndrome can occur from benign conditions that might not alter life expectancy. Here we present a case of a superior vena cava (SVC) obstruction caused by soft tissue encircling the SVC, which was strongly suspected of being an unusual focal type of fibrosing mediastinitis. A 39-year-old man with no prior medical history presented with a four-week history of facial plethora, headache and dilated veins of the neck with a dark purple color change on the anterior chest wall. Radiology examinations, including venography, and computed tomography with a 3-dimensional volume-rendering image of the chest, had revealed severe narrowing of the SVC due to tiny encircling soft tissue and collateral vessels. A total occlusion of the SVC occurred as a result of a thrombus that developed within 1 day after the diagnostic SVC angiogram. The patient underwent stent deployment three days after the administration of thrombolytic therapy.