Superior vena cava syndrome masquerading as an allergic reaction.

Patients are often referred to the emergency department for further evaluation, yet the astute physician will maintain a broad differential to avoid anchoring on prior diagnoses. In this case, a 56-year-old man was referred to our emergency department from the radiology suite secondary to concerns for an “allergic reaction” to prior magnetic resonance imaging contrast. Upon presentation, he was noted to have facial swelling with ruddy appearance and vascular congestion extending to the midchest region; no airway compromise or dyspnea was noted. He had a smoking history and recent diagnosis of brain mass, which, combined with his current appearance,was concerning for superior vena cava syndrome. A chest x-ray that demonstrated right mediastinal mass was ordered, and a computed tomographic scan confirmed compression of the superior vena cava. A brief discussion on the history, etiologies, presentation, and evaluation of superior vena cava syndrome is discussed.