Most common intracranial tumour encroaching the orbit is
Astrocytoma
Glioblastoma multiforme
Sphenoid wing meningioma
Medulloblastoma
The intracranial meningiomas which secondarily invade the orbit are arising from the sphenoid bone. Orbital invasion may occur through: floor of anterior cranial fossa, superior orbital fissure and optic canal. Ref khurana page no.423
Tumors