Differentials
Micropenis due to another cause
SIGNS / SYMPTOMS
Isolated micropenis suggests inadequate testosterone production.
Some cases are due to hypogonadotrophic hypogonadism (patients may also present later with delayed puberty and no ambiguity of the genitals), growth hormone deficiency (short stature, poor growth), or a genetic syndrome (e.g., Prader-Willi syndrome).
Patients typically have normal testes palpable, no hypospadias, and a normal 46,XY karyotype.
INVESTIGATIONS
Requires investigation for abnormalities of congenital hypopituitarism and disorders of testosterone biosynthesis.
Unilateral undescended testis (cryptorchidism)
SIGNS / SYMPTOMS
Patients with isolated unilateral undescended testis have no micropenis, no hypospadias, and a normal 46,XY karyotype.
Extremely common in normal boys, especially preterm infants.
Bilateral abdominal testes are not common and further evaluation is indicated.
INVESTIGATIONS
Clinical diagnosis.
Ultrasound abdomen/pelvis may be used to locate the testes.
No further hormonal evaluation is indicated if this is an isolated finding.
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