MRCP2-3030

A 68-year-old man with a history of angina presents with worsening difficulty in walking throughout the day. He denies back or leg pain and has not experienced any trauma. After 4 hours in the Emergency Department, his condition worsens and he is now unable to stand and complains of urinary retention. On examination, he exhibits flaccid paralysis with hyperaesthesia in the T12 dermatome and reduced sensation below this point, while vibration sensation and proprioception remain intact. A palpable bladder is also noted. What is the most likely diagnosis?