👉 Fibrocystoma is a type of benign tumor that occurs in the breast and can be caused by many factors. It's usually not cancerous, but it can cause pain or discomfort when it grows larger. The exact cause of fibrocystic breast disease (FBCD) is not fully understood, but some theories suggest genetic mutations, hormonal changes, or a combination of these factors. Some people have FBCD due to a family history of the condition, while others develop it independently.