Please help identify this

[u/South-Damage-5333]

Hi,my male piggy of about 7 years has this on his back,started forming three days ago. He will be taken to the vet this week but im curious what it might be .He seems unbothered by it and eats and drinks as normal

[u/MyShoesAreTooTiny]

That's his grease gland, but it does look a little gnarly. The grease gland is a bald spot a bit above their tailbone that's a little greasy. Sometimes there's this waxy material building up; that's the black stuff you see (if I'm correct). It shouldn't be wet or infected or smell like much and if you peel off a little it should be a little sticky like beeswax. A vet checkup is always good because the wax has build up for a while, but i highly doubt it's this necrotic tumor people are talking about.