ESPE Abstracts

Introduction: Isolated micropenis is a common presentation to a pediatric endocrine clinic causing significant parental anxiety. Little is known about the dose and duration of treatment as well as long-term outcomes in such children.

Aim: To identify the course and predictors of puberty in boys with isolated micropenis.

Method: Records of 102 boys presenting with isolated micropenis (stretched penile length < -2.5 SDS for age) from December 2014 – March 2024 were reviewed. Those who did not receive treatment and those with incomplete data were excluded. Baseline data included age at presentation, presence of anosmia, anthropometry, stretched penile length and pubertal assessment using Tanner method; investigations included LH, FSH, Testosterone level. Inhibin-B levels were done where feasible to differentiate self-limiting delay in puberty from hypogonadotropic hypogonadism. Pubertal staging and SPL was serially monitored until attainment of SPL within the normal range. Dose of testosterone received and increment in penile size were noted. Boys were reassessed between 12-14 years of age and onset of puberty was observed in 57 subjects. Predictors of normal pubertal onset were studied.

Results: The mean age at presentation was 8.7 ± 4.4 years (0-15.4 years). The mean stretched penile length at initial presentation was 3.0 ± 0.9cm. The mean dose of testosterone received was 42.8 mg ± 17.6 mg intramuscular monthly. The mean percentage increase in SPL with a single dose of testosterone was 32.7 ± 24.1 % (0-100%) and percentage increase from baseline after last dose of testosterone was 72.9 ± 39.7% (9.1-200%). Normal pubertal onset was seen in 48 (84.2%) subjects (11 self-limited delayed puberty) and hypogonadism in 9 (15.8%) subjects. Subjects with hypogonadism had a comparable age (7.5 ± 6.8 years as against 11.5 ± 2.2 years, P = 0.12) and a smaller SPL at presentation (2.4 ± 1.2 cm as against 3.5 ± 0.8 cm, P = 0.03). The percentage increase in SPL with testosterone therapy was not statistically significant in the two groups (114.0 ± 58.9% in hypogonadism versus 71.3 ± 40.9% in those with normal puberty, P = 0.2). The final SPL (5.1 ± 1.8 cm versus 5.8 ± 0.8 cm, P = 0.4) and the cumulative dose of testosterone received (130.5 ± 79.8 mg versus 122.9 ± 74.4 mg, P = 0.8) were comparable in both the groups.

Conclusion: Normal pubertal onset is seen in most boys presenting with isolated micropenis. Smaller SPL at presentation predicts higher likelihood of delayed puberty. There is a need for multi-centric study with long-term follow-up of these children.