http://commons.wikimedia.org/wiki/Special:Log/Sigma1986
The first files he uploaded were images of underage femalia genitalia, however the account was never blocked. In fact, some of his images managed to slip through some foreign language Wikipedias in the relevant pages about female anatomy, and remained there for some time before being detected. After they were deleted, the files were re-uploaded.
By reading between the lines it seems that the account belongs to a now over-18 woman who took the pictures herself while she was young; or a boyfriend who took pictures of the girlfriend. In theory. In reality, it could just be yet another fake.