So here is a nine year old boxer named Milo who had a very aggressive tumor called a malignant neurofibroma growing on his shoulder.

The middle yellowish layer is dense with agents that are believed to stop an arthritic agent known as interleukin 1, which causes degeneration of the joints and the breakdown of cartilage.

They are also distinct from the pseudorosettes of an ependymoma which consist of tumor cells with glial fibrillary acidic protein (GFAP) positive processes tapering off toward a blood vessel (thus a combination of the two).

So that white material that you see in between the bark and the wood is the mycelial felt of the fungus, and what it's doing it's actually slowly strangling the tree to death by preventing the flow of water and nutrients.