This has an unusual appearance with a fluid-fluid level in a cystic structure. Consideration was given to a hemorrhagic cyst but this would be unusual given the breast surgery was more than two years ago.

The cyst, which was located close to the surgical scar, was aspirated under ultrasound guidance with thick white fluid aspirated from the solid dependent portion and clear serous fluid from the anechoic portion - this confirms this as a chyloma/seroma.