A 67-year-old man with prostate cancer presented with acute polymyositis and vocal cord paralysis as a result of mediastinal lymphadenopathy. His clinical course was unusual, with the development of a malignant pleural effusion, supraclavicular adenopathy, and osteolytic bone lesions. Urologic symptoms developed only pre-terminally, and osteoblastic bone metastases were not documented. This case suggests that prostate cancer need not have a simple natural history.