Lipomas of the major central veins are very rare tumors that have mostly been described in the inferior vena cava. They are often incidentally revealed by computed tomography or magnetic resonance imaging. Histological examination is unusual. We report the case of a lipoma of the superior vena cava discovered on computed tomography performed after a thoracic trauma in a 55-year-old man. The tumor was surgically removed and the fatty nature of the mass was established.