females and present with beast carcinomas that arise from lobules in ~1% of all cases and ducts in 89% of all cases; these values in women are 8% and 73%, respectively. the commonest histopathology-defined type of mbc is, as it is in females, invasive ductal carcinoma (also termed invasive carcinoma of no special type). the other histopathologically-defined types of mbc in descending order of frequency include ductal carcinoma in situ, papillary carcinomas of the breast (occurs in each of its four subtypes, in situ, encapsulated, solid-paapillary, and invasive papillary carcinoma), medullary breast carcinoma, mucinous carcinoma, inflammatory carcinoma, phyllodes tumor, leiomyosarcoma of the breast, paget's disease of the breast, and invasive lobular carcinoma. mammary secretory carcinoma and invasive cribriform carcinoma of the breast which in recent studies have accounted for more than 3% and 1.7%, respectively, of mbc cases, can be added to near the top of this list whereas tubular carcinoma of the breast, a subtype of the invasive ductal carcinomas, occurs but is extremely rare in men. female breast cancers have a far greater number of types (see breast cancer types) than those reported for men. this may reflect the rarity of many female breast types combined with the rarity of male breast cancer. gene mutations two inherited gene mutations critically associated with the development and/or progression of breast cancer occur in the tumor cells of mbc and female breast cancer but with different frequencies: brca2 mutations occur in 12% of males and 5% of females while brca1 mutations occur in 1% of males and 5-10% of females. these mutations are the two most frequent causes of the hereditary breast–ovarian cancer syndrome, a syndrome associated with increased risks of developing not only breast cancer but also ovary cancer, prostate cancer, and less commonly pancreatic cancer and melanoma. since men without a history of breast cancer who carry a mutation in a brca2 or brca1 gene have increased rates of developing prostate cancer, screening for prostate cancer in men with beast cancer who are 45 years or older and carry a brca2 gene mutation is strongly recommended and should be considered for men with a brca1 gene mutation. the national comprehensive cancer network recommends self-breast examination starting at age 35 for men with mutations in either brca gene. mutations in other genes such as chek2, palb2, pten, atm and rad51l3 (also termed rad51d) have been reported to occur uncommonly in, and may confer an increased risk of developing, mbc. these genes are uncommon causes of the hereditary breast-ovarian syndrome but for the most part are associated with breast but not the other cancers in men. mutations in the latter genes also occur in female breast cancer and are associated with ovarian as well as breast cancer. the rates of these mutations in male vs. female breast cancer have not been defined. breast cancer in the cowden syndrome is associated with pten gene mutations, in the li-fraumeni syndrome with tumor protein p53 gene mutations, and in the lynch syndrome with mutations in any of the four dna mismatch repair genes (mlh1, msh2, msh6, pms2), or the epcam gene. the relative risks of men vs. women with these inherited syndromes developing breast cancer are unclear. treatment and prognosis similar to breast cancer tumors in women, mbc tumors are treated by surgical removal, radiotherapy, chemotherapy, immunotherapy, and/or hormonal therapy. however, there are key differences in these treatments between the two sexes. the most common surgical treatment for mbc tumors has been total mastectomy with breast-conserving surgery being performed in a much smaller proportion of males than females. this difference may be due to men generally having smaller breasts, tumors more often located beneath the areola, tumors more often involving nipples and/or skin, and tumors more often having smaller and narrower resection margins than women. these conditions increase the probability that breast-conserving surgery will leave some tumor cells behind and therefore increase the rate of tumor recurrences. furthermore, sentinel lymph node biopsies (i.e. biopsies of the armpit lymph node nearest to the tumor) pose challenges because there are anatomical differences in lymph node drainages around the breasts between women and men that can lead to misidentifications of sentinel lymph nodes in men. in spite of these reservations, a recent review of 14,061 mbc cases found no statistically significant difference in the overall survival rates of men treated with mastectomy vs. breast-conserving surgery at 5 years (49.4% vs. 54.7, respectively) and 10 years (19.7 vs. 25.1%, respectively). the study also found that: a) men treated with adjuvant radiotherapy (i.e. radiotherapy in addition to other treatments) had significantly higher 5 year overall survival rates than men not treated with radiation therapy (59.4% v.s. 44.5%, respectively); b) tamoxifen therapy improved overall survival rates compared to treatments not using tamoxifen at 5 years (81.7 vs. 71.4, respectively) and 10 years (57.9 vs. 50.4, respectively); c) tamoxifen therapy improved 5 year overall survival rates compared to therapy with aromatase inhibitors (i.e. medicines that block the production of estrogens); and d) therapy with an aromatase inhibitor plus a gnrh agonist (i.e. medicines that indirectly inhibit production of estrogens, progesterone, and androgens) improved the 5 year overall survival rate over an aromatase inhibitor without a gnrh agonist; tamoxifen is routinely and very commonly prescribed for treating all stages of mbc. indeed, studies suggest that the first-line treatment of choice for metastatic male (but not female) breast cancer is tamoxifen with chemotherapy being reserved for mbc cases that are estrogen receptor-negative or become unresponsive to tamoxifen plus highly symptomatic. other studies have found that the prognosis of mbc, similar to female breast cancer: depends on their cancer's tnm stage; that stage for stage, the prognoses of mbc appears similar to that in female breast cancer; and that mbc has a somewhat lower 5-year overall survival rate than female breast cancer (82.8% vs. 88.5%, respectively). however, men with breast cancer tend to have additional comorbidities including serious neoplasms and are more likely to die from other causes compared to women with breast cancer. it is suggested that disease-specific survival rate (i.e. percentage of individuals who have not died from breast cancer) would be a more accurate measure of mbc treatment efficacies, prognoses, and survivals than overall survival rates (i.e. the percentage of all individuals who are alive at an indicated time after initial treatment regardless of the cause of death) and should be reported in future studies on mbc.