PLE-2427

A 72-year-old man with hypertension has had increasingly severe back pain over the past 2 months. He had a myocardial infarction 4 years ago. He has marked tenderness over T11, T12, L1, and L2. An x-ray film of the lumbosacral spine shows osteoblastic lesions in these vertebrae. What is the most likely diagnosis?