In 1993 Engelbert Knosp et al. offered the Knosp grade system for showing invasion of cavernous sinus by pituitary macroadenoma. Briefly, the much laterally adenoma grows and surrounds the internal carotid artery (ICA), the more grade level is. The grading defined by the relation of carotid lines with the limits of invasion. These lines passes through supra- and intracavernous internal carotid artery in coronal view. There are medial, median and lateral carotid lines 1).
The first edition of the World Health Organization Classification of Tumors of the Central Nervous System was published in 1979 and took almost a decade to complete.
Biallelic inactivation of the NF2 gene has been established as the principal underlying genetic event in patients with sporadic and syndrome-associated vestibular schwannoma (VS). Two independent teams contemporaneously identified the NF2 gene located on chromosome 22 at 22q12.2 in 1993, which codes for the tumor suppressor protein Merlin, also called schwannomin