[A case of pyoderma gangrenosum involving the prostate gland after radiation therapy for prostate cancer].

A 76-year-old man complained of difficulty in urination and miction pain with abacterial pyuria after radiation therapy for prostate cancer. Transurethral resection of the prostate was performed and histopathologically widespread necrosis was observed in the prostate. Thereafter retention of urine and fever occurred and computed tomography scan revealed an abscess of the penile corpus. The abscess was drained, but the fever continued. He developed an abacterial lung abscess and abacterial necrotic ulcerating lesions on his back, his left leg and his lower abdomen. Macroscopic findings demonstrated typical features of pyoderma gangrenosum. Steroid treatment was initiated and the response to steroid therapy was dramatic. Finally urinary diversion using an ileal conduit was performed. We found few cases of pyoderma gangrenosum involving lesions other than those of the skin in the literature. This is the first report of pyoderma gangrenosum involving the prostate gland after radiation therapy for prostate cancer.