Seminoma in Klinefelter's syndrome with 47, XXY, 15s+ karyotype.

A 32-year-old man was found to have seminoma of the right testis which had been subjected to orchiopexy for cryptorchism 14 years earlier. The left testis was small and firm, and the patient was further studied for hypogonadism. Chromosome analysis revealed a karyotype of 47, XXY, 15s+ with an extra X chromosome and enlarged and fluorescent satellites on chromosome 15. The satellites were also found in the mother as well as in two sisters and one brother out of his four siblings. Endocrine studies, histological pictures of the biopsied left testis and dermatoglyphic analysis were compatible with Klinefelter's syndrome. To our knowledge this is the first reported case of seminoma associated with the syndrome. Several implications are discussed for the rare occurrence of a germinal cell tumor in Klinefelter's syndrome.