A ___________ is the most common benign brain tumor and typically arises from the sphenoid bone before it invades the orbit.

• A. Astrocytoma
• B. Schwannoma
• C. Hemangioblastoma
• D. Meningioma

Answer: (D)

Meningioma. These tumors arise from the meninges, are typically extra-axial, and frequently occur near the skull base such as the sphenoid wing. Because of that location, they can remodel bone and extend into the orbit through skull base openings, leading to proptosis or blurred vision, which is a classic way they present with orbital involvement. Meningiomas are also the most common benign intracranial tumors and tend to grow slowly.

In contrast, astrocytomas originate from brain parenchyma (astrocytes) and are intra-axial, not tied to bone. Schwannomas come from nerve sheath cells, often in the cerebellopontine angle, and hemangioblastomas are vascular tumors usually in the cerebellum or retina; neither typically starts from the sphenoid bone or invades the orbit in the same common pattern.