Carcinoma of the male breast and Klinefelter's syndrome: is there an association?

There appear to be no substantial data to confirm the assumption that breast cancer in men with Klinefelter's syndrome is as common as breast cancer in the normal female population. The number of reported cases of breast cancer in Klinefelter's males is only 27, a number too small for any meaningful statistical analysis. There is evidence, however, to suggest that Klinefelter's males have an increased risk of breast cancer that approaches three percent. Physicians should therefore be aware of potential breast pathology in XXY males and incorporate a careful breast examination and specific education into the routine health maintenance of men with Klinefelter's syndrome.