We report the case of a 28 year-old female, who gave birth seven weeks previously, presenting with a pulmonary artery leiomyosarcoma discovered on a thoracic CT performed for clinical suspicion of pulmonary embolism. This case presents two major points of interest: on the first hand, it is a particular context (young post-partum patient), with classic symptoms of routine pulmonary embolism. On the other hand, the exam clearly demonstrates tumor enhancement, which is characteristic but rarely described.