We report on a 20-year-old man in whom endocrinological investigation owing to dysmorphic signs characteristic for Turner syndrome revealed mixed gonadal dysgenesis. The patient was referred to us for further diagnostic investigations on a right intrascrotal tumour. Both testes were intrascrotal and hypotrophic with normal testosterone production. Surgical investigation showed a circumscribed tumor that proved to be a rudimentary uterus without evidence of malignancy at histological examination. Biopsies from both tested showed no signs of malignant disease. After removal of the tumor, we decided not to remove the testes prophylactically because of the male phenotype and the sufficient testosterone production.