Lump on the side of our lovebirds neck?

Hey, my mom has had her love bird for almost 15 years now, hes been healthy the whole time, she hand fed and raised him on her own, but we took him out today for the first time in a while and noticed that there was a bulge sticking out a little out of the left side of his neck, does anyone know a bit about birds? anyone have any ideas? im hoping its not what i think it is but its good to know now the possibilities hope to hear back from some1 soon, your friend, trish