A 30 year old Caucasian male from São Paulo was admitted to the hospital He had been complaining about constant, moderate pain in the anterior and lateral left hemi-thoracic region for the last three months as well as associated great effort dyspnea over the last month.Investigation with chest X-rays, CT scans and MRI revealed a large anterior and medial mediastinal tumor suggesting large vessel invasion. The patient was submitted to a left side parasternal mediastinostomy and a biopsy of the mediastinal mass which was complicated by severe bleeding. An immediate median full sternotomy was elected in addition to a left anterior-lateral thoracotomy for total tumor resection and control of the bleeding. Evolution was good, with hospital discharge on the ninth postoperative day. The anatomical-pathological essay disclosed a hemangioendothelioma of the mediastinum.

Keywords: Hemangioendothelioma/diagnosis. Mediastinal neoplasms.