micropenis

Micropenis is a clinical finding characterized by an unduly small penis for age and stage of development. It is defined by a stretched penile length (SPL) well below the normal range, commonly cited as more than 2.5 standard deviations below the mean for age. The condition may be present at birth (congenital) or become apparent during childhood when penile growth is reduced relative to peers. It can occur alone or as part of broader disorders of sexual development.

Causes include disorders of androgen production or action, such as congenital hypogonadotropic hypogonadism or Leydig cell dysfunction leading to low testosterone; enzyme deficiencies affecting androgen metabolism, such as 5-alpha reductase deficiency; androgen insensitivity syndromes; and prenatal exposure to estrogens or other antiandrogenic compounds. Genetic or chromosomal conditions may also play a role. In some cases, no clear cause is identified.

Evaluation involves careful measurement of SPL, physical examination for other genital or systemic abnormalities, and laboratory assessment (gonadotropins, testosterone, DHT, thyroid and growth hormone status, karyotype when indicated). Imaging or genetic testing may be used to identify underlying causes.

Management aims to address the underlying cause and potential penile growth. In cases of hormone deficiencies, hormone replacement (e.g., testosterone) may promote penile growth, especially if therapy is begun before the end of puberty. In other conditions, targeted treatments or multidisciplinary care are used. Psychological support and counseling are advised for affected individuals and families. Fertility and sexual function depend on the overall etiology and treatment response.

Micropenis has a favorable prognosis with timely diagnosis and appropriate therapy in many cases, but outcomes vary with cause and treatment access.