Priapism as the initial manifestation of a penile and lower limb cutaneous metastasis of prostate adenocarcinoma with low serum PSA level.

Penile and/or cutaneous metastases from prostate adenocarcinoma rarely occur. Here, we detail the case of a 78-year-old man suffering from priapism caused by metastatic prostate cancer with both penile and lower limb cutaneous spread. His serum prostate-specific antigen level was 0.09 μg/L when priapism developed. Corpora cavernosa biopsy was refused by the patient and radical penectomy was performed. Postoperative pathologic and immunohistochemical studies revealed undifferentiated prostate adenocarcinoma cells growing in corpora cavernosa. Two months later, the patient presented with multiple, erythematous nodules over the right lower leg. The prostate-specific antigen level was found to be 0.264 μg/L. Biopsy of a skin nodule revealed neoplastic cells consistent with metastatic prostate adenocarcinoma. This is the first known case of metastatic prostate cancer found in both penis and skin with a low serum prostate-specific antigen level. Priapism presented as the initial clinical manifestation of metastatic prostate cancer.