Never seen this before.
Never seen this before.
This is what I see, which is how I cropped in on it.
@the Puts me in mind of a papilloma infection / outbreak. Rabbit papilloma often creates that squared off outline, but deer growths are supposed to be more rounded.
If you do look that up, be ready for deer having a very not good time.
Not trying to dox you, but there is a plague of this stuff hitting deer from Wyoming to Ohio right now. Some of those states are asking for reports about these deer so they can track/contain the outbreak. 
Interesting. I'm in New Mexico.