Micropenis in Children and Adolescents: A Narrative Review

Narrative review of 36 studies: early testosterone therapy beats surgery for micropenis, but RCT data barely exists

Journal: International Brazilian Journal of Urology | Published: 2026 | Type: Narrative Review | PMID: 41576180 Authors: Salvador Edson da Silva, Favorito Luciano A (Universidade do Estado do Rio de Janeiro) Funding/COI: Funding not listed; no conflicts of interest declared

Summary

Micropenis — penile length more than 2.5 standard deviations below the mean for age — is most commonly a sign of an underlying endocrinopathy, particularly Congenital Hypogonadotropic Hypogonadism. This narrative review screened 707 records and selected 36 studies to summarize diagnosis and treatment. The bottom line: early testosterone therapy has the best-supported evidence, surgical approaches remain methodologically murky, and the field badly needs randomized controlled trials.

Claims

• Micropenis is frequently associated with Congenital Hypogonadotropic Hypogonadism (CHH) rather than being an isolated anatomical finding
• Accurate diagnosis requires Stretched Penile Length (SPL) measurement using population-specific nomograms — general reference ranges are unreliable across ethnic groups
• A newer measurement technique, SPLINT (Stretched Penile Length INdicator Technique), is described as improving diagnostic standardization
• Testosterone therapy shows greatest efficacy when initiated in early infancy, with reported significant penile growth and generally favorable functional outcomes
• Spontaneous catch-up growth during puberty has been reported in select cases, supporting expectant management in some presentations
• Surgical interventions have limited, heterogeneous evidence and inconsistent long-term results; the review explicitly states surgery should not be considered first-line

Study Quality

This is a narrative review, not a systematic review or meta-analysis. The authors screened 707 records and selected 36 — but narrative reviews apply no standardized inclusion criteria or quality scoring, so selection bias is a real concern. The conclusions rest on whatever 36 papers the authors judged relevant; without a PRISMA table or GRADE assessment, it's impossible to audit that judgment.

The review correctly identifies the core problem with this literature: no randomized placebo-controlled trials exist. Every treatment claim is built on observational data, case series, and cohort studies of varying size and follow-up duration. The call for better-designed prospective studies is warranted but also an admission that current evidence cannot support firm recommendations.

Red Flags

• Narrative review design: no systematic selection criteria, no pooled analysis, high risk of cherry-picking
• Funding source not disclosed — particularly relevant given one of the co-authored techniques (SPLINT) is described and promoted within the paper
• 36 studies from 707 screened is a 5% inclusion rate with no stated PRISMA methodology to justify exclusions
• No quantitative effect sizes reported for testosterone therapy outcomes — "significant penile growth" without numbers is not informative
• Long-term adult outcomes (fertility, sexual function, psychological wellbeing) are acknowledged as lacking but not quantified

Strengths

• Clearly states what the evidence cannot support: surgery is explicitly called out as having insufficient evidence for routine use
• Highlights the methodological importance of population-specific nomograms, a clinically relevant and often ignored point
• Comprehensive search date (October 2025) means the literature covered is current
• Authors are from a urology department with research infrastructure (UERJ's Urogenital Research Unit)

Verdict

This paper is useful as an orientation map to a thin literature, not as evidence-based guidance. The honest conclusion — no RCTs, surgery unsupported, early hormonal therapy looks promising but lacks controlled data — is more valuable than the review's framing suggests, precisely because it documents how little solid evidence exists. The narrative format and undisclosed funding are legitimate concerns, but the paper's intellectual honesty about evidentiary gaps makes it worth a read for anyone trying to understand the state of this field. Don't cite it for numbers; cite it for the gap it describes.