How rare is male breast cancer ?

Very rare.: Less than 1% of all cases of breast cancer diagnosed in the us annually are in men. The lifetime risk of a man developing breast cancer is about 1:1000. Men can inherit the hereditary risk for breast cancer (brca mutations), but, even then, the lifetime risk of actually developing breast cancer is less than 20%.

1/1000 lifetime: Here is a number stating 1 in 1, 000 lifetime chance of a man to get breast cancer in his lifetime, though I have also seen a 1 in 10, 000 number. http://www.medicinenet.com/male_breast_cancer/article.htm to me, male breast cancer is a marker for possible brca mutation, especially in a jewish family, and should prompt a discussion for testing for hereditary breast/ovarian cancer syndrome.

Rare: It is quite rare. Presents as a painless lump under tge nipple most often over age 65. Less than 1% of breast cancers occur in men.