Strictly defined familial male breast cancer.

The term "familial male breast cancer" is often misleading, because in the breast cancer families reported in the literature, the vast majority of the patients were women and only a few were men. In this report, we present the rare case of a strictly defined familial male breast cancer (MBC) in which exclusively men were diagnosed with breast cancer. Three of four brothers developed the disease between the age of 46 and 64 years within a period of 21 years whereas all female relatives remained unaffected. The three affected men did not show the typical known clinical and genetic risk factors for MBC. An X-linked recessive inheritance may be possible in these cases. One way to potentially improve the identification of the causes of MBC could be a through a strictly studying families in which the male members were exclusively diagnosed with this malignancy. This approach emphasizes familial MBC as a distinct entity and not only as a variant of female breast cancer.