Breast cysts may be found in one or both breasts. Signs and symptoms of a breast cyst include: 
A smooth, easily movable round or oval lump that may have smooth edges — which typically, though not always, indicates it's benign
Nipple discharge that may be clear, yellow, straw colored or dark brown
Breast pain or tenderness in the area of the breast lump
An increase in breast lump size and breast tenderness just before your period
A decrease in breast lump size and resolution of other symptoms after your period
 Having breast cysts doesn't increase your risk of breast cancer. But having cysts may make it harder to find new breast lumps or other changes that might need evaluation by your doctor. Your breasts may feel lumpy and painful when you're menstruating, so it's important to be familiar with how your breasts feel throughout your menstrual cycle so that you'll know if something changes.