The things we learn in med school...
Well, this actually wasn't covered in class. It was passed on to me by a fellow classmate. Nonetheless, I found it just too... unique... to not post immediately.
Chronic penile oedema secondary to chronic masturbation. Int J STD AIDS. 2004. Jul;15(7):489-90.
*Added 15 Feb in response to comment:
Oedema, more commonly spelled edema, is swelling of tissues due to excessive fluid accumulation.