Introduction: Rupture or acute dissection are the major complications of thoracic aortic aneurysms and can be fatal. The mortality of ruptured thoracic aortic aneurysm at 6 hours is 54 percent and at 24 hours reaches percent. Methods: We present the case of a 53 year old male, without any previous cardiovascular history, who presented at the emergency department for sudden onset of back pain. Chest radiograph raised the suspicion of aortic aneurysm, diagnosis confirmed by the computer tomography that revealed multiple aortic aneurysms (maximum diameter of the ascending, arch and descending thoracic aorta of 57, 63, and 73 mm, respectively). No intimal flap was identifying in the transthoracic echocardiography. Serodiagnostice tests were positive for syphilis (RPR and TPHA). During preoperative evaluation, the patient presented hemorrhagic shock and the CT examination revealed the rupture of the descending thoracic aortic aneurysm in the left pleura. Results: Emergency intervention was performed with descending thoracic aortic replacement with graft under extracorporeal circulation. The postoperative evolution was favorable. Postoperatively, the dermatological examination set the diagnosis of late latent syphilis and appropriate therapy was installed. The patient was discharged 24 days after surgery. Conclusions: Although rare in the antibiotic era, tertiary syphilis should be considered in the differential diagnosis of thoracic aneurysms in patients with poor socioeconomic status, while the long-term management of these patients remains a real therapeutic challenge.