Even though men don't have breasts like women, they do have a small amount of breast tissue. The "breasts" of an adult man are similar to the breasts of a girl before puberty. In girls, this tissue grows and develops, but in men, it doesn't.
But because it is still breast tissue, men can get breast cancer. Men get the same types of breast cancers that women do, but cancers involving the parts that make and store milk are rare.
Incidence and Mortality
Estimated new cases and deaths from breast cancer (men only) in the United States in 2013:
New cases: 2,240.
Male breast cancer is rare. Less than 1% of all breast carcinomas occur in men.[3,4] The mean age at diagnosis is between 60 and 70 years, though men of all ages can be affected with the disease.
Predisposing risk factors  appear to include radiation exposure, estrogen administration, and diseases associated with hyperestrogenism,...
It is rare for a man under age age 35 to get breast cancer. The chance of a man getting breast cancer goes up with age. Most breast cancers happen to men between ages 60 and 70. Other risk factors of male breast cancer include:
Diseases of the testicles such as mumpsorchitis, a testicular injury, or an undescended testicle
How Serious Is Breast Cancer in Men?
Doctors used to think that breast cancer in men was more severe than it was in women, but it now seems that it's about the same.
The major problem is that breast cancer in men is often diagnosed later than breast cancer in women. This may be because men are less likely to be suspicious of something strange in that area. Also, their small amount of breast tissue is harder to feel, making it harder to catch these cancers early. It also means tumors can spread more quickly to surrounding tissues.
What Are the Symptoms of Breast Cancer in Men?
Symptoms of breast cancer in men are similar to those in women. Most male breast cancers are diagnosed when a man discovers a lump on his chest. But unlike women, men tend to delay going to the doctor until they have more severe symptoms, like bleeding from the nipple. At that point the cancer may have already spread.