"fat-fluid level within cyst: when fat and water are present, and the milk is in a fresh liquid state, a characteristic fat-fluid level is seen due to the viscosity difference. This can be demonstrated on mediolateral view with the beam horizontal to the upright patient."
"Galactoceles, also known as lactoceles, are the most common benign breast lesion typically occurring in young lactating women; however, they mostly develop following the cessation of lactation 1."