Welcome to the forum! From the info that you have given here it sounds like the cyst may be causing your daughters seizures. The neuro. can do an e.e.g. but that won't always show any damage or activity in the brain because sometimes the activity that's causing the seizures is to deep for an e.e.g. to show. Also your daughter is at the age of puberty and this is another thing that can cause seizures do to hormones changing.
You should get your daught to see an Epileptologist (Dr. specializing in epilepys) and be sure you take her to an Epilepsy Center which are usually at University or big hospitals. I've had epilepsy for 40 yrs. and my seizures started on the right temporal lobe of the brain which is on the right side of the brain just above the ear and the left temporal lobe is in the same location only on the left side of the brain. The frontal lobe is where the forehead is.
Your daughter needs to cut out the carbs and starch foods because they will trigger seizures and tell her to start eating foods high in fats, this will build keytones in her body and the keytones help reduce the seizures.
Start keeping track of your daughter seizures by writing them down on a calendar be sure to write down what time they happen and a discription of the seizure. By doing this the Dr. may see a pattern in your daughters seizures. I personally don't feel that your daughter is having psuedo seizures meaning fake seizures I have a feeling this is all do to the cyst she has and that's probably the reason why she is having pain in her leg also. Get your daughter on vitamin B12 500 mcg. once a day, keep her off the cell phone because they have been proven to cause brain tumors, and keep her away from anything with nutra sweet in it because nutra sweet causes more electrical activity in the brain which can trigger seizures. I wish you and your daughter only the best and May God Bless the both of You!