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Man With Micropenis Responds to Testosterone

— Therapy helps Kallmann syndrome patient

Last Updated May 31, 2016
MedpageToday

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ORLANDO -- A man with and an abnormally small penis gained more than half an inch when he started taking testosterone, researchers reported here.

The testosterone therapy increased the 26-year old's serum testosterone and "resulted in a satisfactory gain in penile length" of 1.5 cm, according to , at the University of Puerto Rico, who presented the findings at a poster session here at the annual meeting of the American Association of Clinical Endocrinologists, which runs through Sunday.

Action Points

  • Note that this study was published as an abstract and presented at a conference. These data and conclusions should be considered to be preliminary until published in a peer-reviewed journal.

"Testosterone treatment seems to be effective in patients with Kallmann Syndrome and micropenis," wrote the authors. "Thus, it may be the primary form of treatment for micropenis in adults with prepubertal characteristics."

The patient had no past medical history but he presented without ever having undergone puberty. His condition was first noticed when he was 15, and he otherwise had normal developmental milestones, according to Ruiz. When Ruiz and colleagues examined him, he had "eunuchoid body proportion," a 1-centimeter penis, a normal scrotum, and small testicles. He had no facial hair, sparse pubic hair, decreased libido, anosmia, and a high-pitched voice, but had a normal karyotype.

The authors reported that his hormone levels were consistent with hypogonadotropic hypogonadism:

  • Follicle stimulating hormones = 1.27 mIU/mL
  • Luteinizing hormones = 0.5 mIU/mL
  • Total testosterone = 0.27 ng/mL
  • Free testosterone = 0.007 ng/mL
  • Sex hormone binding globulin = 13.7 nmol/L

"Other pituitary hormones were within normal levels," wrote the authors.

"When we were first questioning him we found out that he couldn't smell anything," said Ruiz in an interview. They subsequently did an MRI, which revealed that he did not have olfactory bulbs in his brain. A human chorionic gonadotropin test was done and the man's plasma testosterone rose from 26 ng/dL to 69 ng/dL.

The changes to the man's testicles came after about 4 months of weekly testosterone treatment, according to Ruiz. His testicles also gained in volume. Ruiz said he doesn't know whether further treatment will result in more growth, but said some evidence from other studies indicates that sometimes treatment can result in a 4-centimeter gain.

"The most important concern in a patient with micropenis is whether he will have sufficient penile growth to allow sexual function," wrote the authors. They plan to continue to work with the patient so that he can eventually become fertile, said Ruiz, although the vast majority of patients with hypogonadotropic hypogonadism don't become fertile. Ruiz said that the patient's libido has increased dramatically and that the patient has noticed seminal fluid coming out of his penis since starting testosterone.

Disclosures

The authors disclosed no relationships with industry.

Primary Source

American Association of Clinical Endocrinologists

Ruiz O, et al "Penile growth in response to hormone treatment in an adult with micropenis and kallman syndrome" AACE 2016; Abstract 1002.