Breast cancer in men is rare, but men do develop it. Male breast cancer accounts for less than 1% of all breast cancer cases. Other than the incidence rate, male breast cancer is similar to breast cancer in women.

All breast cancer begins when normal cells in the breast change and begin to grow uncontrollably, eventually forming a tumor. A tumor can be benign (noncancerous) or malignant (cancerous).

Breast tissue is composed of mostly fatty tissue. Growing within the breast tissue there is a network of tube-like structures called lobules. In the lobules are the milk glands (yes, men too have milk glands). There is also a system of tiny ducts that connect the glands, lobules, and lobes to the areola (the dark area surrounding the nipple). The breast also contains blood and lymph vessels that both nourishes the breast cells and drains bodily waste. The lymph vessels are connected to bean shaped organs (lymph nodes) which fight infections.

Most breast cancer cases start in either the ducts or lobes of the breast. Almost 75% of all breast cancers are called ductal carcinomas and begin in the cells that line the milk ducts. However, approximately 25% of male breast cancers begin in the lobules (lobular carcinoma).

Invasive or infiltrating carcinomas of the breast are cancers that have spread outside of the duct and moved into the surrounding tissue. The majority of male breast cancer cases are infiltrating ductal carcinomas (IDC).

When the cancer has not spread is called insitu, meaning it has stayed “in place.” Ductal carcinoma insitu (DCIS) is the most common type of insitu breast cancer in women, but it is uncommon in men.

Inflammatory breast cancer makes up about 1% to 5% of all breast cancers. Paget’s disease of the nipple, which is more common in men than women, begins in the ducts and sprea