Lady 45 age, applied with nausea, vomiting, and headache that started since 3 months. Physical examination revealed monoparesis in the left lower extremity and hypoesthesia on the left but was otherwise normal.

MRI showed an extra-axially located cystic lesion with a thin wall in the premedullary location compressing brain stem. (see both img of T1W Sagittal and FLAIR transverse) Whats the problem and how move forward?