Skip to main content
. 2016 Nov 23;78(2):164–172. doi: 10.1055/s-0036-1594239

Table 2. California staging system for classification of direct skull invasion for skin cancers.

Superficial Tumor invasion is between the skin and the skull or skull base periosteum.
Intermediate Tumor invasion involves the bone of the skull or skull base.
Deep Tumor invasion extends through the bone of the skull or skull base and involves the dura or brain parenchyma.