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From the Research
Definition of Micropenis
- Micropenis is defined as a penis with a stretched penile length of less than 2.5 SD below the mean for age or stage of sexual development 1, 2, 3, 4.
- In neonates, micropenis is defined as a penile length of less than 2 cm 2, 4.
- In children above 1 year of age, micropenis is defined as a stretched penile length of less than 1.9 cm 1.
- Micropenis should be differentiated from a buried or hidden penis and aphallia 1.
Diagnosis and Evaluation
- Diagnosis of micropenis should be made using a standard technique of stretched penile measurement and nomograms for age 1.
- Evaluation of micropenis should include history-taking, physical examination, specific hormonal testing, and chromosomal and imaging examinations if necessary 4.
- Basal and human chorionic gonadotropins (HCG)-stimulated gonadotropins, testosterone, DHT, and androstenedione levels should be assessed 2.
- Karyotype assessment is equally important in the evaluation of micropenis 2.
Etiology and Classification
- Micropenis can be classified as due to deficient testosterone secretion or action 3.
- Etiologies of micropenis include hypothalamo-pituitary disorders, genetic syndromes, partial gonadal dysgenesis, testicular regression, and disorders of testosterone biosynthesis and action 2.
- Micropenis can be associated with hypospadias, incomplete scrotal fusion, and cryptorchidism, which are suggestive of disorders of sex development (DSD) 2.