Table of Contents 21-1

Micropenis: Long-term Follow-up

These authors report the long-term outcomes of 46,XY males with micropenis, but no other genital deformity, identified and treated intermittently with androgens or hCG during infancy, childhood and/or adolescence. Lee and Houk determined adult stretched penile length (SPL) and social adjustment in 20 patients with SPL <–2 SD of normal at initial examination: 11 had hypogonadotropism and 3 primary testicular failure; in 6 patients no cause of the micropenis was identified. SPL increased in all subjects; adult SPL was >–2 SD of the adult mean in 14 subjects and between –2.5 and –2 SD in 4; 2 patients had adult SPL <–2.5 SD of the mean. Among these 20 patients and another 2 with micropenis first evaluated as adults, 21/22 were heterosexual; 8 were/had been involved in long-term heterosexual relationships. Relative to age-matched control subjects, those with micropenis (N=12 studied) had comparable findings in regard to heterosexual dating and sexual functioning, male friendships, education, employment, sports/leisure activities; none had a psychiatric illness. Despite normal adult SPL, 5 primarily obese patients stated that their penises were small. The investigators concluded that in adult men who had micropenis as children/adolescents: 1) 90% had adult SPL within the broad range of normal; 2) there was “reasonable social adjustment,” no psychological pathology, and gender-appropriate sexual functioning.

Husmann evaluated adult SPL in 20 men with micropenis (here defined as SPL <–2.5 SD of normal) diagnosed and treated during infancy in whom SPL did not increase appreciably despite multiple courses of testosterone. Five patients had a mutation in the androgen receptor, 6 had hypogonadotropism, and 9 had no known cause of the micropenis. Mean pretreatment SPL was –3 SD (range –5.5 to –2.6) for age/race and mean adult SPL was –3.4 SD (range –5.9 to –2.2). All patients considered their penises to be small, and 5 had undergone (unsatisfactory) surgery to enlarge their penises; 19/20 were heterosexual; 12/20 men were sexually active, but 4 were incapable of vaginal penetration; 5 patients had mental illnesses requiring professional therapy. Despite these findings, Husmann concluded that these patients accept a male gender identity and many engage in a “satisfying heterosexual relationship.”

Lee PA, Houk CP. Outcome studies among men with micropenis. J Pediatr Endocrinol Metab 2004. 17:1043-53.

Husmann DA. The androgen insensitive micropenis: Long-term follow-up into adulthood. J Pediatr Endocrinol Metab 2004.17:1037-41.

Editor’s Comment: In the report of Lee and Houk, in 5/20 patients (1 hypogonadotropic subject, 1 with primary testicular failure, and 2 with “idiopathic” micropenis) SPL SD score did not appreciably increase between diagnosis and adulthood, but these subjects are not specifically discussed further, and their psychosocial status is unknown. It would have been of interest if Husmann had also reported his experience with the outcome of patients with micropenis responsive to testosterone. These data are reassuring in that they further demonstrate that there is no basis to consider sex reversal in the 46,XY male with micropenis as their gender identity is firmly masculine. Furthermore, with current surgical procedures for penile reconstruction, the opportunity for satisfactory penile enlargement has improved substantially.¹

Allen W. Root, MD

Reference - (linked to )

1. Jordan GH, Rosenstein DI, Gilbert D. Growth Genet Horm 2002;18:33-8.