What is the treatment approach for micropenis in adults?

Treatment Approach for Micropenis in Adults

Testosterone therapy is the first-line treatment for micropenis in adults, with the goal of achieving adequate penile length for normal urination, sexual function, and positive self-image. 1, 2

Diagnostic Criteria

• Micropenis is defined as a structurally normal but abnormally small penis with stretched penile length (SPL) 2.5 SD below the mean for age 2
• In adults, this typically means a stretched penile length below 4 cm 2
• Must be differentiated from buried penis, hidden penis, or aphallia 3

Evaluation Process

• Comprehensive hormonal evaluation including:
  • Basal and HCG-stimulated gonadotropins (LH, FSH) 2
  • Testosterone and dihydrotestosterone (DHT) levels 2
  • Androstenedione levels 2
• Karyotype assessment to rule out genetic causes 2
• Imaging studies (ultrasound) to evaluate testicular position and size 4

Etiological Classification

• Hypogonadotropic hypogonadism (hypothalamic or pituitary failure) 3
• Hypergonadotropic hypogonadism (testicular failure) 3
• Partial androgen insensitivity syndrome 3
• Idiopathic causes 3

Treatment Algorithm

First-Line Treatment: Hormonal Therapy

• Intramuscular testosterone enanthate injections:
  • Starting with 25-50 mg monthly, gradually increasing to adult replacement dosage of 200 mg monthly 5
  • Multiple courses may be required to achieve optimal results 5
• Alternative options:
  • Topical testosterone preparations 1
  • Topical 5α-dihydrotestosterone (DHT) gel 1, 2
  • Recombinant FSH and LH for specific cases 2

Response Assessment

• Monitor penile growth response after initial testosterone course 3
• Studies show testosterone therapy can increase adult penile length to within 2 SD of the mean, with final lengths of 8-14 cm reported 5
• Continue treatment if positive response is observed 3

Adjunctive Measures

• Psychological counseling to address body image concerns and sexual confidence 1
• Management of any associated hormonal deficiencies (e.g., growth hormone deficiency) 3

Important Considerations

• Early intervention provides better outcomes, but adult treatment can still be beneficial 2
• Treatment aims should focus on achieving functional adequacy for urination and sexual function 2
• Surgical options have limited role and variable satisfaction outcomes in adults 2
• Regular follow-up is essential to monitor response and adjust treatment as needed 3

Treatment Efficacy

• Studies demonstrate that testosterone therapy can result in significant penile growth even when initiated in adulthood 5
• Long-term studies show that properly treated patients can achieve normal sexual function and male gender identity 5
• Most patients treated with testosterone achieve penile lengths sufficient for normal sexual function 5

Potential Pitfalls

• Delayed diagnosis and treatment may result in suboptimal outcomes 4
• Failure to identify and treat associated hormonal deficiencies can limit treatment success 3
• Inadequate psychological support may lead to persistent body image issues despite physical improvement 1
• Unrealistic expectations about final penile size should be addressed early in treatment 2