title: Bilateral male breast cancer with male potential hypogonadism.
abstract: BACKGROUND
  Male breast cancer is a comparatively rare disease, and simultaneous bilateral male breast cancer is considered to be an extremely rare event. Risk factors are said to be genetic factors and hormonal abnormalities due to obesity or testicular diseases.
  
  
  METHODS
  The patient was a 47-year-old Japanese male. His family had no history of female breast cancer. This patient also had hypospadias and hormonal examination indicated the presence of primary testicular potential hypogonadism, and these hormonal abnormalities seemed to be present since childhood or the fetal period. The bilateral breast cancer developed in this man at a comparatively young age, and histopathological studies of multiple sections showed that there was almost no normal epithelial cell in the ducts, while the ducts were almost completely filled with breast cancer cells.
  
  
  CONCLUSIONS
  It is thought that male breast cancer is caused by an imbalance between estrogen and testosterone. We cannot rule out the possibility that the breast cancer developed due to the effect of the slight elevation of estrogen over a long period of time, but the actual causative factors in this patient were unable to be definitively identified. In the future, we hope to further elucidate the causes of male breast cancer.
authors.affiliation: Department of Oncological and Regenerative Surgery, Institute of Health Biosciences, The University of Tokushima, 3-18-15, Kuramoto-Cho, Tokushima 770-8509, Japan. hirohiro@clin.med.tokushima-u.ac.jp
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Hirose
authors.forename: Mitsunori
authors.initials: M
authors.lastname: Sasa
authors.forename: Yoshimi
authors.initials: Y
authors.lastname: Bando
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Hirose
authors.forename: Tadaoki
authors.initials: T
authors.lastname: Morimoto
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Kurokawa
authors.forename: Taeko
authors.initials: T
authors.lastname: Nagao
authors.forename: Akira
authors.initials: A
authors.lastname: Tangoku
mesh_terms: D001707:Biopsy, Needle; D018567:Breast Neoplasms, Male / Q000175:diagnosis* / Q000209:etiology / Q000601:surgery*; D005500:Follow-Up Studies; D006801:Humans; D007006:Hypogonadism / Q000150:complications / Q000175:diagnosis* / Q000188:drug therapy; D007021:Hypospadias / Q000150:complications / Q000175:diagnosis* / Q000601:surgery; D007150:Immunohistochemistry; D008297:Male; D008327:Mammography / Q000379:methods; D008408:Mastectomy / Q000379:methods; D008875:Middle Aged; D016896:Treatment Outcome; D018608:Ultrasonography, Doppler