cystic porencephaly versus cystic encephalomalacia

My 8 year old daughter was diagnosed with new-onset partial epilepsy from a brain insult at birth.  She has a 4cm cystic encephalomalacia in the left parietal lobe.  What is the difference between encephalomalacia and porencephaly?  Are they different or the same thing.  Also, the area is very focal and can be operated on if seizures are not controlled by medicine. she has had no developmental delays and cognitively she is grade appropriate in school.  Are we fortunate at this point that she has not developed any other neurological problems?  The neuro-sugeon said the cystic area (cavity) will not change over time and is very distinct according to her mri.  Can these things grow?  Also, what are her chances of outgrowing this type of epilepsy?  I have heard that as her brain matures the hope is that the area will eventually die out and she could become seizure free without surgery.  It has taken years for this epilepsy to develop.  Is that common?

any help would be appreciated.