Breast cancer and interstitial cell tumor in a patient with Klinefelter's syndrome

Abstract

An elderly man with carcinoma of the breast was found to have a benign interstitial-cell tumor of the testis. His karyotype was XXY, and his urinary excretion of estriol was increased. It is concluded that the abnormal hormonal environment in the man with Klinefelter's syndrome may cause the development of both testicular interstitial-cell tumor and of breast cancer. Chromosome and hormone studies of men with these neoplasms, and complete clinical examination of patients with Klinefelter's syndrome are desirable.