A 58-year-old man presented with dysuria at the Osaka Medical College Hospi
tal in November 1996. Laboratory examination revealed elevated serum prosta
te-specific antigen (PSA) to > 100 ng/mL. Adenocarcinoma of the prostate wi
th metastasis to the bone was diagnosed after a biopsy of the prostate and
bone scintigraphy; hormonal therapy was administered. Although bone metasta
sis was well controlled and the serum PSA level declined to within normal l
evels (2.0 ng/mL), several painless nodules were found on the penile glans.
Biopsy of the nodules showed that the penile tumor was a metastasis from t
he prostate cancer. The patient underwent partial penectomy for relief from
penile pain. The serum PSA level showed no elevation 3 months after the pa
rtial penectomy, suggesting that careful observation of prostate cancer pat
ients is necessary, even when oseous metastasis is well controlled and seru
m PSA levels are kept within normal ranges by hormonal therapy. The case al
so indicates that urologists should consider the possibility of metastasis
to the penis from prostate cancer.