It’s a big one. Hole that is. This practitioner is certain to get everything out if they need to shine a light in and send in a search party. They might even hear an echo.
This is an old cyst with a thick wall that is starting to break down, so the contents are going from white chunks to pink and goopy to blood. No infection yet.
It looks like medfolk might have been in the neighborhood doing a procedure for something else and decided to clean this up too.