To better understand breast cancer in males, it helps to understand the anatomy of the breast.

Breasts are made of fat and milk glands. Small passageways, called ducts, deliver milk from the glands, to the nipple. Lymphatic tissue provides a passageway for cell waste to drain from the breast.

Males usually have very small amounts of breast tissue. Breast tissue requires the hormone estrogen to grow and function. Since most men have little estrogen in their bodies, breast tissue remains inactive. Rarely, the ducts and other breast cells present in males can become cancerous.