A 58-year-old man presented with an eight year history of troublesome recurrent erections during sleep. He awakes three or four times each night with a painless erection but can achieve rapid de-tumescence by standing, walking around or voiding. The erections never occur while he is active during the day and he does not have any history of priapism lasting greater than four to six hours. He also has normal erectile function with normal ejaculation and libido.

There is no history of any recent illnesses or any perineal injury in the past and he is not on any medication. He denies any lower urinary tract symptoms and has a normal PSA.

An abdominal examination revealed the external genitalia to be unremarkable. Rectal examination revealed a small benign prostate and there was no evidence of any peripheral adenopathy.