CASE 33: Female 38y/o patient with intermitent headache

This was an outpatient with history of intermitent and refractary headaches over the past 5 years. She had no history of diseases, medications, or previous trauma. CT scan (not shown) performed in other center was apparently normal but neurologist wasn't satisfied with it. 

Here are the relevant images:

Thank you to TecniScan Diagnostic Center here in Guatemala city for providing me with these case.

Findings?

Later, as always..the conclusion.