Polyarteritis nodosa mimicking prostatic cancer.

We describe a 72-year-old man with prostate enlargement, prostate-specific antigen level of 35 ng/dl, mild polyarthritis, and constitutional symptoms. Prostatic ultrasonography suggested neoplasm; however, transrectal biopsy revealed findings consistent with polyarteritis nodosa (PAN). The patient went on to develop leg paresthesia and dysesthesia, increased serum creatinine, and systemic hypertension. Steroids and intravenous cyclophosphamide were administered, followed by improvement. Our case emphasizes the protean onset of PAN, and provides a new differential diagnosis of prostatic diseases related to elevated prostate-specific antigen.