What is a "Pentecostal Catholic"? One of my new neighbors is a "Pentecostal Catholic" from India.  I have heard of this denomination before, during an Evangelical Missiological Society conference, but didn't have a reason to investigate further until now.

What is a "Pentecostal Catholic"?

I'm familiar with Catholicism and Pentecostalism, so feel free to explain it in terms of the main differences between one (or both) of those denominations if that makes it simpler.

NOTE: I am not looking for an exhaustive explanation of all of their doctrines, just a "what you need to know" sort of thing; i.e. What do they emphasize?  What's the back-story?
The only time I've encountered similar labels was when people were talking about the Charismatic Renewal, which is a Catholic approach to speaking in tongues, baptism of the Spirit, etc.

Having come from a Protestant denomination, the outward manifestations do not strike me as terribly different, but the Catholics are clearly Catholic in other practices and theology.