It appears as though, much like how Microsoft announced the slimmer, smaller Xbox One S in addition to the upgraded Xbox One Scorpio, Sony too will be announcing a PS4 Slim in addition to the PS4 Neo. Apparently, the slimmer PS4 will be revealed by the Tokyo Game Show this year.
The PS4 Slim has not yet been officially confirmed, or even mentioned by Sony- but chances are that Sony will reveal it at the same time as the Neo, possibly as a replacement for the base PS4 model. The Neo has been officially confirmed by Sony, but nothing further is known about the system other than that it exists.
Source: Rheena.com