Metastatic prostatic carcinoma mimicking a unilateral sacroiliitis.

We describe a 65-year-old male who presented with unilateral sacroiliitis as the first manifestation of metastatic prostatic carcinoma. When progressive symptoms are unresponsive to conventional therapy, a reconsideration of the diagnosis is necessary with appropriate further imaging studies. We discuss the differential diagnosis of sacroiliitis including, mechanisms of joint involvement in malignancy, and present a review of the literature.