A male case of synchronous double cancers of the breast and prostate i
s reported. An 84-year-old male was admitted to the hospital complaini
ng of general malaise, anorexia and weight loss. A tumor 3 cm in diame
ter was noted in his left breast, which was removed by mastectomy, and
was diagnosed as papillotubular carcinoma. An induration of his prost
ate and elevated prostate specific antigen, gamma-seminoprotein and pr
ostatic acid phosphatase levels were also noted. Needle biopsy of his
prostate revealed adenocarcinoma. Among the previous 18 reported cases
of this combination of cancers, those with no prior estrogen therapy
were very rare, the present case being the third ever reported.