RESUMEN
Gonadoblastoma occurs almost always in association with a Y chromosome cell line, and developes in one third of patients with Mixed gonadal dysgenesis. Removing of gonads of intersex patients with the Y chromosome is very important because of the strong association of the genesis of tumor in dysgenetic gonads with the presence of a Y chromosome. But it is always possible that an XY cell line could be missed, or that a fragment from Y chromosome could have been translocated and not discovered by chromosomal analysis. PCR with Y specific probe or Southern blotting would reveal the presence of a Y or a translocated fragment. We experienced an 18-year-old woman represent with primary amenorrhea who had 45,X/46,X,+mar. Y-specific PCR revealed that the marker chromosome was drived from Y chromosome. After both gonadectomy and clitorial recession, we found the gonadoblastoma in dysgenetic testis. So we report it with brief review of literatures.