Cory Cat Disease

Hey my cory cat has this big white tumorous thing and I am not sure what it is I am thinking that it is a lymphocyte but I am just not sure. It is currently in quarantine just in case.

Not seen anything like that before.  Hopefully someone will come along with some insights for you.
Can you tell us, how long have you had the Cory? 
Has anything changed in the tank recently, feeding live food, new fish etc?
 
Just a thought, it is not a parasite of some sort that has attached itself to your Cory?

I have had him for four months now and the only thing that has changed is that every now and again I will give them Hikari frozen blood worms and have been treating the tank preemptively for ich due to a friend cross contaminating by accident, there wasn't an outbreak and I just stopped treating. The ich solution is the Kordon Ich attack.

That is a strange protrusion.  Is there a chance of a close-up from the other side to where it may "attach" to the fish?
 
 
Parasite seems to be a logical conclusion.  How long has it been there?