Question and Answers About Mixed Gonadal Dysgenesis

Q. My son, age 15, has mixed gonadal dysgenesis. His genitalia are normal although he is lagging behind in maturation. His lab results show a low level of testosterone. How much of a risk is there for testicular cancer?

We have had a wide range of recommendations from getting a biopsy to having examinations every three months. We do not want to become overly alarmed about the possibility of cancer but want to be knowledgeable.

We are aware of the use of gonadectomy in Turner's Syndrome girls, but I don't think it applies to our son's case. What particular variables make our son more at risk than the rest of the population? What would you recommend as reasonable preventive steps? Thank you. Julie

Dear Julie,
Thanks for your tough questions. The problem with deciding what is best for your son depends on two issues. First, what is the risk of getting a tumor? Gonadoblastomas (type of testes cancer) are rare tumors in the general popula-tion but are associated with gonadal dysgenesis and, more specifically, the Y chromatin.

Female outward appearance and intra-abdominal testes also are risk factors. Your sons chromosomes have a mixture of XY and XO so the risks are not clear.

If all patients with the Y chromosome were known to develop tumors, then there would be no question to remove the testes (orchidectomy). Actually, about 25 percent of streak gonads form gonadoblastoma. Your son is probably also at risk of developing other types of testicular cancers.

Some recommendations take into account the ability to monitor the testes for tumors. If your son decides not to have surgery, he will need to perform a self-testicular exam at least once a month. If his exam changes, he will need urgent medical evaluation. If his testicles are up too high in the groin, where he could not easily palpate (feel) them for abnormalities, the tumor may become big before he notices it.

Secondly, does your son need his testicles to have a successful life? Will he be distressed more by being reminded he has something wrong every time he does his exam? Since he is not getting much testosterone from his testes and since fertility has not been documented in this patient population, keeping his testicles for this reason only is probably irrational.

After orchidectomy, administration of testosterone will help him catch up in growth, secondary sex characteristics and possibly in self-esteem.