Malignant Testicular Tumors in Brothers

TESTICULAR TUMORS are uncommon, comprising 0.7% of all malignant neoplasms in males in one large survey.1The majority are found in men 20 to 40 years of age. The highest incidence occurs between the ages of 29 and 34 years during which period they are the most common malignant tumor in males.2 Malignant testicular tumors occurring in brothers have been reported in only five sets of twins and three sets of nontwins. In addition, the rare tumor, gonadoblastoma, has been reported in 6-year-old monozygous twins with a pure gonadal dysgenesis who were phenotypically female but who had a 44 A-XY karyotype.3 Champlin4in 1930 reported the first cases of testicular tumors in twins. He described identical twins, one of whom developed a sarcoma of the right testicle seven years before his brother developed an embryonal carcinoma—so called round cell sarcoma, also of the right testicle. Domrich