A 42-year-old woman with metallic valve prosthesis in aortic position, in use of oral anticoagulant, presented a sudden syndrome of medullary compression, characterized by intense dorsal pain and partial paralysis of the inferior portion of the body, progressing to flaccid paraplegia of the arms and legs with level of sensibility in T-2. Large extradural spinal hematoma of the thoracic spine was diagnosed by magnetic resonance with medulla compression in the proximal portion. The patient was underwent to surgery (decompressive laminectomy), however with little motricity improvement and the level of sensibility. Due to respiratory insufficiency the patient died.