Final answer:
Fine Needle Aspiration (FNA) is the recommended additional study to assess the contents of the cyst in the breast.
Step-by-step explanation:
The additional study that could be recommended to assess the contents of the cyst in the breast is Fine Needle Aspiration (FNA). FNA is a minimally invasive procedure in which a thin needle is used to remove a sample of cells or fluid from the cyst for analysis. It can help determine if the cyst is benign or malignant and guide further treatment.