Breasts are naturally lumpy and bumpy, so most lumps you feel are not cancer, and many times those lumps are harmless cysts. In the simplest terms, breast cysts are pockets of fluid in the breast tissue, and doctors will often leave them alone. However, it’s always good to have lumps checked out as a precaution. In this video, Dr. Marissa Weiss offers some professional advice about dealing with lumps in the breasts