The Surgical Implications of the Arachnoid Membrane in Skull Base Tumors

Based on developmental anatomy and microsurgical observations this report will show that Pituitary Adenomas, Meningiomas and Vestibular Schwannomas are extra-Arachnoid lesions. In contrast, Craniopharyngiomas can have a variable relationship to the Arachnoid and Pia Mater. Craniopharyngiomas can be intra-pial adhering to the neuro-ectoderm, and they can be intra- or extra-Arachnoid. These relationships have specific surgical implications that influence outcomes.