The terms “male breast” and “male mammary gland” are both used in medical literature. Experimental and clinical studies demonstrate a similar origin and development of hyperplastic processes in breast in men and women, as well as common etiology and pathogenetic mechanisms of development of breast carcinoma in male and female organisms. The international standard for anatomical terminology (Terminologia Anatomica 1998) omitted the separate term “mamma masculine” because the male breast contains no unique elements but those of the female breast developed to a lesser extent. In the European and North American literature, several terms are used for breast carcinoma both in women and in men along with the Latin term “cancer mammae.” The common term in English is “breast cancer,” but with reference to men, the additional word “male” is applied. © Springer International Publishing Switzerland 2015.