The authors report a case of leiomyosarcoma of the descending thoracic aorta presenting with dissection and operated as an emergency. Palliative repair from the oncological point of view comprised the insertion of an aorto-aortic tube. Local radiotherapy was completed by a course of chemotherapy controlling multiple bone and adrenal metastases at 15 months. A review of the literature did not reveal any other cases of haemorrhagic leiomyosarcoma of the descending thoracic aorta. Histological findings were similar to those of the reported case as were the therapeutic attitudes to limit or extinguish disseminated metastases explained by the arterial character of the tumour.