Can anyone identify this mass I found when I did my duck's autopsy??

[Deborah M]

I had to euthanize my runner duck yesterday. I wish I had taken more and better pictures but just didn't, it was a hard day all around. Attached are two images of a large mass that was attached to the crop (in the uncut pic the reddish/pinkish area on the top left is where it was attached). In the pic where I cut into the mass the heart is there for scale. It filled his entire chest cavity. I also found another much smaller mass like this one that was attached to the other side of the crop but also to the musculature/bones where his wing attached to his body (he was unable to fully extend his right wing). The weight of that mass made it difficult for him to stand upright like runners do, his posture was horizontal by the end). Again I wish i had better pictures but I wasn't thinking right. If anyone has any ideas please feel free to share. The mass has kind of squishy soft sort of like liver. Is this a tumor?

 

[raingarden]

fatty tumor?

 

[Deborah M]

fatty tumor?

That's what I was wondering. It doesn't really look like any other tumors I've been able to find.