If you take the right steps you certainly can cure piriformis syndrome. While there are many different ways you could go about doing so, I've had the most success with a combination of PNF, AIS, and Myofascial Release/Neuromuscular Therapy.
PNF and AIS:
What I tend to do is loosen up surrounding tissues using rope stretching and a few other AIS methods. When it comes to the piriformis, though, I tend to use PNF (although I use AIS as well) with a leg on a counter/bench. I advoate this method primarily because you don't always have a partner to do PNF with, and I also have a better grasp on teaching/using AIS through some time with Mark Verstegen.
Myofascial Release/Neuromuscular Therapy:
If you have the means and or access to a soft-tissue therapist, it is the clear cut way to go. If not, you can improvise. Like AIS/PNF; I instruct athletes to release the surrounding tissues (Back–> Hamstrings–> Adductors–> Quads –> Abductors–> Calves–> Glutes–>More specific work on the piriformis itself). We'll usually begin on a foam roll or basketball, then as the superficial layers loosen, we'll move into a more dense object like a lacrosse ball. I will say that although this is very effective, nothing is superior to the hands/elbows of a professional; so if this type of manipulation doesn't do the trick I highly recommend finding a skilled therapist.
Hope this answers some of your questions.