Dear Karel, The only way of knowing if this is indeed a cancer problem and not related to a benign (non-cancerous) condition is to have it further examined, possibly biopsied. Cancer generally spreads through the blood or lymphatic system, this is why frequent sites of metastasis are the lymph nodes, organs, or bone. Fat is not involved in the metastatic process of breast cancer, and would not be a buffer to prevent spread.
Hormones are chemical substances in the body secreted by various glands (for example: thyroid, pituitary, adrenal, testis) that have an effect on other tissues or organs throughout the body. Hormonal imbalances can produce various symptoms depending on the function of the specific hormone. When you are examined by the physician they will discuss with you any other symptoms you may have and combining that information with your physical exam may give a clue as to a possible link between what you may be experiencing and a hormonal imbalance.