Objective To improve the diagnosis of common male breast diseases by studying their clinical and full field digital mammography(FFDM) findings.Methods Twenty-eight male patients(mean age,58 years;range,2677 years) underwent FFDM,which indicated 27 male with breast hypertrophy and 1 male breast cancer.Their clinical and FFDM findings were analyzed.Results The imaging appearance of male breast hypertrophy on FFDM was characterized as following: 1)localized pathy-like hypertrophic gland behind the mammary areola(n=18);2)diffuse,discal hypertrophy of the whole breast(n=5);3)gland hyperplasia companied by ductal hyperplasia(n=4).The imaging finding of breast cancer on FFDM was demonstrated by a well-defined,dense mass medially behind the nipple with low-density shadow and fine cluster calcification focus in the mass.The inquiry of patient’s history is helpful in defining the etiology.Conclusions The differential diagnosis between the male breast hypertrophy and breast cancer based on their clinical and FFDM features respectively is feasible. Diagnosis should be made with discretion when a combination of the both diseases is doubt.