Where is the growth located on the tree? I suggest you take photos of the tree and close ups of the growth and send them to <personal data hidden> for them to take a look and tell you what is going on. 

I wasn't sure if a picture of the tree trunk was needed for positive ID so I sent ya one too.
Thank you for your time.
 I can't tell if the attachments worked. Let me know if they didn't.

Based on the photos and the fact that there appears to be only one of these in the tree, I strongly suspect one of the gall forming insects. There are many of them, so it's hard to know which one is involved here without cutting the growth open and looking to see if there are larva inside. You can remove this by simply pruning it out. If you are interested in which insect might be involved you can cut the growth out and bring it to the plant clinic at the extension office.

Interesting! There were a few of these clumps, not a lot. Never thought about an insect . Well thank you. Never too old to learn something new!