If a brain tumor grows threw your skull what will it look like and feel like?

Stinky: Brain tumors would not erode the skull, but would push in the brain causing death long before visible. Skin cancers like squamous or basal cells, if ignored for years or decades, could eventually rot their way through the skin, muscle and possibly bone into the brain. It would look like a festering wound, but due to the slow progress, would likely not cause agonizing pain.